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PRODID:Mathematics Seminar Calendar
BEGIN:VEVENT
UID:20221202T001943-29376@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Skew Products: Coactions You Can See
DESCRIPTION:Speaker\: Lucas Hall, MSU\r\nThe speaker introduces topological quivers and constructs their associated C*-algebra. We present two independent constructions which arise in the presence of a cocycle (the topological ”skew product" and the algebraic coaction) and show that the constructions agree in a suitable sense. Along the way, we characterize the skew product based on some associated topological dynamics. Time permitting, we will explore future directions.
LOCATION:C304 Wells Hall
DTSTART:20220906T150000Z
DTEND:20220906T155000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29376
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29397@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Organizational Meeting
DESCRIPTION:Speaker\: G&T Seminar, MSU\r\nOrganizational meeting for the GT seminar this Fall.
LOCATION:C304 Wells Hall
DTSTART:20220906T190000Z
DTEND:20220906T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29397
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29378@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Heat smoothing conjecture and Bernstein--Markov inequalities on Hamming cube
DESCRIPTION:Speaker\: Sasha Volberg, MSU\r\nHamming cube and its various Poincaré type inequalities represent a crucial model for many questions ranging from Banach space theory to graph theory to theoretical computer science. We present some estimates for tail spaces on Hamming cube. We use the analytic paraproduct operator for that. We also show some Bernstein--Markov inequalities, here the novelty is in getting rid of some irritating logarithms.
LOCATION:C304 Wells Hall
DTSTART:20220907T201000Z
DTEND:20220907T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29378
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29391@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Pattern-avoiding parking functions
DESCRIPTION:Speaker\: Lara Pudwell, Valparaiso University\r\nWe extend the classical definition of patterns in permutations to parking functions. In particular we study parking functions that avoid permutations of length 3. A number of well-known combinatorial sequences arise in our analysis, and this talk will highlight several bijective results. This project is joint work with Ayomikun Adeniran.
LOCATION:Online (virtual meeting)
DTSTART:20220908T190000Z
DTEND:20220908T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29391
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29383@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Floating mats and sloping beaches: spectral asymptotics of the Steklov problem on polygons
DESCRIPTION:Speaker\: Leonid Parnovski, University College London\r\nI will discuss asymptotic behaviour of the eigenvalues of the Steklov problem (aka Dirichlet-to-Neumann operator) on curvilinear polygons. The answer is completely unexpected and depends on the arithmetic properties of the angles of the polygon.
LOCATION:C304 Wells Hall
DTSTART:20220908T201000Z
DTEND:20220908T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29383
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BEGIN:VEVENT
UID:20221202T001943-29409@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Symplectic groupoid and cluster algebra description of closed Riemann surfaces
DESCRIPTION:Speaker\: Leonid Chekhov, Michigan State University\r\nWe use the Fock-Goncharov higher Teichmuller space directed networks to solve the symplectic groupoid condition: parameterize pairs of $SL_n$ matrices (B,A) with A unipotent such that $BAB^T$ is also unipotent. A natural Lie-Poisson bracket on B generates the Goldman bracket on elements of A and $BAB^T$, which are simultaneously elements of the corresponding upper cluster algebras. Using this input we identify the space of X-cluster algebra elements with Teichmuller spaces of closed Riemann surfaces of genus 2 (for $n$=3) and 3 (for $n$=4) endowed with Goldman bracket structure: for $g$=2 all geodesic functions are positive Laurent polynomials and Dehn twists correspond to mutations in the corresponding quivers. This is the work in progress with Misha Shapiro.
LOCATION:C304 Wells Hall
DTSTART:20220912T163000Z
DTEND:20220912T173000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29409
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29401@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Making Weight
DESCRIPTION:Speaker\: Brent Nelson, MSU\r\nA weight on a von Neumann algebra is a positive linear map that is permitted to be infinitely valued. It is a generalization of a positive linear functional that arises naturally in the context of crossed products by non-discrete groups, and they are vital to the study of purely infinite von Neumann algebras. In this talk I will provide an introduction to the theory of weights that assumes only the definition of a von Neumann algebra.
LOCATION:C517 Wells Hall
DTSTART:20220912T200000Z
DTEND:20220912T213000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29401
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29377@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:A Liouville-esque theorem for a weakly-defined derivation on B(H)
DESCRIPTION:Speaker\: Lara Ismert, Embry–Riddle Aeronautical University\r\nLiouville’s Theorem states that any bounded entire function on the complex plane is necessarily constant. In this talk, we discuss an analogous theorem for a weakly-defined derivation on B(H) studied in recent years by Erik Christensen. As a consequence, we provide new sufficient conditions for when two operators which satisfy the Heisenberg Commutation Relation must both be unbounded.
LOCATION:C304 Wells Hall
DTSTART:20220913T150000Z
DTEND:20220913T155000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29377
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BEGIN:VEVENT
UID:20221202T001943-29410@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Superspace, Vandermondes, and representations
DESCRIPTION:Speaker\: Brendon Rhoades, UCSD\r\nWe present an extension of the Vandermonde determinant from the polynomial ring to superspace. These superspace Vandermondes are used to construct modules over the symmetric group with (occasionally conjectural) connections to geometry and coinvariant theory. Joint with Andy Wilson.
LOCATION:Online (virtual meeting)
DTSTART:20220914T190000Z
DTEND:20220914T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29410
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29412@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Organizing meeting for Student Number Theory Seminar
DESCRIPTION:Speaker\: Jie Yang, MSU\r\nIn this first meeting, I'll give some motivations towards the study of p-adic modular forms, and explain some central concepts in "eigenvarieties machine" introduced by K. Buzzard. In the end, we will discuss the plan for this seminar.
LOCATION:C204A Wells Hall
DTSTART:20220915T190000Z
DTEND:20220915T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29412
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29402@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Stability patterns in configuration spaces
DESCRIPTION:Speaker\: Jenny Wilson, University of Michigan\r\nThis talk will give an introduction of the recent field of 'representation stability'. I will discuss how we can use representation theory to illuminate the structure of certain families of groups or topological spaces with actions of the symmetric groups, focusing on configuration spaces as an illustrative example.
LOCATION:Online (virtual meeting)
DTSTART:20220915T201000Z
DTEND:20220915T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29402
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29415@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Super-Resolution on the Two-Dimensional Unit Sphere
DESCRIPTION:Speaker\: Anna Veselovska, Department of Mathematics, Technical University of Munich, Germany\r\nIn this talk, we discuss the problem of recovering an atomic measure on the unit 2-sphere S^2 given finitely many moments with respect to spherical harmonics. The analysis relies on the formulation of this problem as an optimization problem on the space of bounded Borel measures on S^2 as suggested by Y. de\r\nCastro & F. Gamboa and E. Candes & C. Fernandez-Granda. We construct a dual certificate using a kernel given in an explicit form and make a concrete analysis of the interpolation problem. We support our theoretical results by various numerical examples related to direct solution of the optimization\r\nproblem and its discretization.\r\n\r\nThis is a joint work with Frank Filbir and Kristof Schroder.
LOCATION:C304 Wells Hall
DTSTART:20220916T200000Z
DTEND:20220916T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29415
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29414@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Cluster structures on SL_n and the Belavin-Drinfeld classification
DESCRIPTION:Speaker\: Alexander Vainshtein, Haifa University\r\nCluster structures were discovered by S. Fomin and A. Zelevinsky about twenty years\r\nago and quickly found applications in various fields of mathematics and mathematical physics.\r\n\r\nIn the latter, several advances were made in a study of classical and quantum integrable\r\nsystems arising in the context of cluster structures. These systems "live" on Poisson-Lie\r\ngroups and their Poisson homogeneous spaces, hence it is important to understand an\r\ninterplay between cluster and Poisson structures on such objects.\r\nIn this talk I will explain a construction of a family of (generalized) cluster structures in the\r\nalgebra of regular functions on SL_n related to the Belavin-Drinfeld classification\r\nof Poisson-Lie structures on SL_n.\r\n\r\nBased on a joint work with M.~Gekhtman (Notre Dame) and M.~Shapiro (MSU).
LOCATION:C304 Wells Hall
DTSTART:20220919T163000Z
DTEND:20220919T173000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29414
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29413@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:All aboard! A mathematical study of transit equity in Baltimore
DESCRIPTION:Speaker\: Craig Gross, MSU\r\nIn 2015, the governor of Maryland canceled a light rail project through the city of Baltimore that had been planned and funded for over a decade. Instead, the money was diverted to funding highways near the richer, whiter suburbs of the city. As Baltimore is home to some of the most extreme class-disparity and segregation in the country, this decision significantly hurt the potential for a more equitable transit system. But by how much?\r\n$\\$\r\nThis talk will be a tour through a mathematical investigation of how the canceled light rail might have increased access to jobs across the city. In particular, we use some dimension-reduction and clustering algorithms on CDC Social Vulnerability Indices to explore which parts of the city may be socioeconomically disadvantaged. We then compute job accessibility metrics to determine how the light rail would have affected these regions. We also give some considerations for converting a collection of many relevant indicators into more interpretable, manageable metrics for future transit studies. \r\n$\\$\r\nThis is joint work with Adam Lee, Kethaki Varadan, and Yangxinyu Xie.\r\n$\\$\r\nThis will be a hybrid seminar and take place in C117 Wells Hall and via Zoom at https://msu.zoom.us/j/99426648081?pwd=ZEljM3BPUXg2MjVUMVM5TnlzK2NQZz09 .
LOCATION:C117 Wells Hall
DTSTART:20220919T170000Z
DTEND:20220919T180000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29413
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29424@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Worth Their Weight
DESCRIPTION:Speaker\: Brent Nelson, MSU\r\nI will continue my introduction to weights. I will briefly mention equivalent conditions of normality for weights before moving onto a discussion of semi-cyclic representations and Tomita-Takesaki theory. I will conclude with a detailed examination of Plancherel weights on locally compact groups.
LOCATION:C517 Wells Hall
DTSTART:20220919T200000Z
DTEND:20220919T213000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29424
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29419@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Spectral estimates of dynamically-defined and amenable operator families (In collaboration with Siegfried Beckus)
DESCRIPTION:Speaker\: Alberto Takase, MSU and UC Irvine\r\nFor dynamically-defined operator families, the Hausdorff distance of the spectra is estimated by the distance of the underlying dynamical systems while the group is amenable.\r\nWe prove that if the group has strict polynomial growth and both the group action and the coefficients are Lipschitz continuous, then the spectral estimate has a square root behavior or, equivalently, the spectrum map is $\frac{1}{2}$-Holder continuous.\r\nWe prove the behavior can be improved resulting in the spectrum map being Lipschitz continuous if the coefficients are locally-constant.\r\nIn 1990, the square root behavior was established for the Almost Mathieu Operator or, more generally, the quasiperiodic operators with Lipschitz continuous potentials.\r\nOur results extend the square root behavior to a bigger class of operators such as (magnetic) discrete Schrodinger operators with finite range and with Lipschitz continuous coefficients.
LOCATION:C304 Wells Hall
DTSTART:20220920T150000Z
DTEND:20220920T155000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29419
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29403@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:$L^2$-Betti numbers of fiber bundles
DESCRIPTION:Speaker\: Bin Sun, Oxford\r\nWe study the $L^2$-Betti numbers of fiber bundles $F \rightarrow E \rightarrow B$ of manifolds. Under certain conditions (e.g., when $F$ is simply connected), $b_*^{(2)}(E)$ can be computed using the twisted $L^2$-Betti numbers of $B.$ We relate the twisted and untwisted $L^2$-Betti numbers of $B$ when $\pi_1(B)$ is locally indicable. As an application, we compute $b_*^{(2)}(E)$ when $B$ is either a surface or a non-positively curved $3-$manifold. This is a joint work with Dawid Kielak.
LOCATION:C304 Wells Hall
DTSTART:20220920T190000Z
DTEND:20220920T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29403
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29425@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Organizational Meeting
DESCRIPTION:Speaker\: \r\n
LOCATION:C517 Wells Hall
DTSTART:20220920T200000Z
DTEND:20220920T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29425
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29416@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:A Diagram-Like Basis for the Multiset Partition Algebra
DESCRIPTION:Speaker\: Alex Wilson, Dartmouth\r\nThere's a classical connection between the representation theory of the symmetric group and the general linear group called Schur-Weyl Duality. Variations on this principle yield analogous connections between the symmetric group and other objects such as the partition algebra and more recently the multiset partition algebra. The partition algebra has a well-known basis indexed by graph-theoretic diagrams which allows the multiplication in the algebra to be understood visually as combinations of these diagrams. I will present an analogous basis for the multiset partition algebra and show how this basis can be used to describe generators and construct representations for the algebra.
LOCATION:Online (virtual meeting)
DTSTART:20220921T190000Z
DTEND:20220921T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29416
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29380@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Conditionally Stable Self-Similar Blowup for the Supercritical Quadratic Wave Equation Beyond the Light Cone
DESCRIPTION:Speaker\: Michael McNulty, MSU\r\nNonlinear wave equations of power-type serve as excellent toy models for geometric PDEs such as the Yang-Mills and wave maps equations. Of great interest in the energy supercritical setting is that of threshold phenomena. In this setting, unstable self-similar blowup solutions are believed to play an essential role in describing the threshold of singularity formation. We will discuss the stability of an explicitly known, unstable self-similar blowup solution of the energy supercritical quadratic wave equation in a region of spacetime which extends beyond the time of blowup. To overcome this instability, we introduce a new canonical method to investigate unstable self-similar solutions. This work represents the first steps toward an understanding of threshold phenomena in the energy supercritical setting.
LOCATION:C304 Wells Hall
DTSTART:20220921T201000Z
DTEND:20220921T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29380
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29438@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Quantizing neural networks
DESCRIPTION:Speaker\: Rayan Saab, University of California, San Diego (UCSD)\r\nNeural networks are highly non-linear functions often parametrized by a staggering number of weights. Miniaturizing these networks and implementing them in hardware is a direction of research that is fueled by a practical need, and at the same time connects to interesting mathematical problems. For example, by quantizing, or replacing the weights of a neural network with quantized (e.g., binary) counterparts, massive savings in cost, computation time, memory, and power consumption can be attained. Of course, one wishes to attain these savings while preserving the action of the function on domains of interest. \r\n\r\nWe present data-driven and computationally efficient methods for quantizing the weights of already trained neural networks and we prove that our methods have favorable error guarantees under a variety of assumptions. We also discuss extensions and provide the results of numerical experiments, on large multi-layer networks, to illustrate the performance of our methods. Time permitting, we will also discuss open problems and related areas of research.
LOCATION:Online (virtual meeting)
DTSTART:20220922T183000Z
DTEND:20220922T193000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29438
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29423@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Modular form and Hecke operator1
DESCRIPTION:Speaker\: Peikai Qi, MSU\r\nIn the talk, we will review the definition of modular form and hecke algebra.
LOCATION:C204A Wells Hall
DTSTART:20220922T190000Z
DTEND:20220922T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29423
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29387@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:K-stability and birational geometry
DESCRIPTION:Speaker\: Chenyang Xu, Princeton University\r\nThe notion of K-stability for a Fano varieties was introduced by differential geometers in late 90s, to capture the existence of a Kähler-Einstein metric. In the last decade, it has gradually become clear to algebraic geometers that K-stability provides a rich algebraic theory in higher dimensional geometry. In particular, it can be used to solve the longstanding question of constructing moduli spaces for Fano varieties. \r\nI will survey the background of K-stability and how algebraic geometers’ understanding of it has evolved. In particular, I will explain algebraic geometry plays a key role of establishing the equivalence between K-stability and the existence of a Kähler-Einstein metric, i.e. the Yau-Tian-Donaldson Conjecture, for all Fano varieties. If time permits, I want to also discuss the construction of K-moduli spaces parametrizing Fano varieties, and how the recipe given by K-stability can be used to resolve the issues that mystify people for a long time.
LOCATION:Online (virtual meeting)
DTSTART:20220922T201000Z
DTEND:20220922T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29387
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29421@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:BD Schubert varieties of parahoric group schemes and global Demazure modules of twisted current algebras
DESCRIPTION:Speaker\: Jiuzu Hong, University of North Carolina at Chapel Hill \r\nIt is well-known that there is a duality between affine Demazure modules and the spaces of sections of line bundles on Schubert varieties in affine Grassmannians. This should be regarded as a local theory. In this talk, I will explain an algebraic theory of global Demazure modules of twisted current algebras. Moreover, these modules are dual to the spaces of sections of line bundles on Beilinson-Drinfeld Schubert varieties of certain parahoric groups schemes, where the factorizations of global Demazure modules are compatible with the factorizations of line bundles. This generalizes the work of Dumanski-Feigin-Finkelberg in the untwisted setting. In order to establish this duality in the twisted case, following the works of Zhu, we prove the flatness of BD Schubert varieties, and establish factorizable and equivariant structures on the rigidified line bundles over BD Grassmannians of these parahoric group schemes. This work is joint with Huanhuan Yu.
LOCATION:C304 Wells Hall
DTSTART:20220926T163000Z
DTEND:20220926T173000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29421
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29427@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Understanding dataset characteristics via diffusion on graph
DESCRIPTION:Speaker\: Remy Liu, MSU\r\nClassical graph signal processing provides powerful techniques for understanding and modifying graph signals from the spectral domain, but they come with high computational costs. More recently, diffusion on graphs has been sought as an alternative approach to modifying graph signals; it is much more computationally efficient and is easy to interpret from the spatial perspective. Here, we present two different studies utilizing diffusion wavelets on a graph to filter graph signals for downstream analysis. In the first study, we aim to understand how and what is being utilized by Graph Neural Networks to achieve graph-related tasks. We do so by observing the performance difference between using the filtered graph and the original graph. We demonstrate that some image datasets, such as CIFAR and MNIST, rely on low-frequency signals; on the contrary, heterophilic datasets, such as WebKB, rely more heavily on high-frequency signals. In the second study on computational biology using gene interaction networks and gene expression data, we observe similar results where different frequency bands perform differently in a task-specific manner. In summary, our studies demonstrate the practical usage of graph diffusion to modify graph signals, leading to improved downstream prediction performance and a better understanding of the graph datasets' characteristics.\r\n$\\$\r\nThis will be a hybrid seminar and take place in C117 Wells Hall and via Zoom at https://msu.zoom.us/j/99426648081?pwd=ZEljM3BPUXg2MjVUMVM5TnlzK2NQZz09 .
LOCATION:C117 Wells Hall
DTSTART:20220926T170000Z
DTEND:20220926T180000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29427
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29417@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Canonical integral models for Shimura varieties defined by tori
DESCRIPTION:Speaker\: Patrick Daniels, University of Michigan\r\nPappas and Rapoport have recently conjectured the existence of canonical integral models for Shimura varieties with parahoric level structure, which are characterized using Scholze's theory of p-adic shtukas. We will illustrate the conjecture using the example of Shimura varieties defined by tori, where (surprisingly) the theory is already nontrivial. Along the way we will explain a connection with the Bhatt-Scholze theory of prismatic F-crystals.
LOCATION:C304 Wells Hall
DTSTART:20220926T190000Z
DTEND:20220926T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29417
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29408@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Conjugate Variables and Dual Systems
DESCRIPTION:Speaker\: Aldo Garcia Guinto, MSU\r\nIn free probability, the semi-circular operators are the analogue of the Gaussian distribution in classical probability. We will be using the semi-circular operators to motivate two notions of free probability: conjugate variables and dual systems. The conjugate variables are used to define free Fisher information, which is analogue of Fisher information in classical probability. While the dual systems are related to a cohomology theory for von Neumann algebras. It turns out that these two notions are not as different as they may seem.
LOCATION:C517 Wells Hall
DTSTART:20220926T200000Z
DTEND:20220926T213000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29408
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29429@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Parking completions
DESCRIPTION:Speaker\: Ayomikun Adeniran, Colby College\r\nParking functions are well-known objects in combinatorics. One interesting generalization of parking functions are parking completions. A parking completion corresponds to a set of preferences where all cars park assuming some of the spots on the street are already occupied. In this talk, we will explore how parking completions are related to restricted lattice paths. We will also present results for both the ordered and unordered variations of the problem by use of a pair of operations (termed Join and Split). A nice consequence of our results is a new volume formula for most Pitman-Stanley polytopes. This is joint work with H. Nam, P.E. Harris, G. Dorpalen-Barry, S. Butler, J.L. Martin, C. Hettle, and Q. Liang.
LOCATION:Online (virtual meeting)
DTSTART:20220928T190000Z
DTEND:20220928T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29429
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29389@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Asymptotics for odd- and even-dimensional waves
DESCRIPTION:Speaker\: Shi-Zhuo Looi, UC Berkeley\r\nIn this talk, I will give a survey of recent and upcoming results on various linear, semilinear and quasilinear wave equations on a wide class of dynamical spacetimes in various even and odd spatial dimensions. These results include asymptotics for a wide range of nonlinearities. We also highlight a dichotomy in odd dimensions between stationary and nonstationary backgrounds and explain how the stationary backgrounds lead to a faster decay rate for waves. \r\n\r\n For many of these results, the spacetimes under consideration have only weak asymptotic flatness conditions and are allowed to be large perturbations of the Minkowski spacetime. We explain the dichotomy between even- and odd-dimensional wave behaviour and how we view this dichotomy as a generalisation of the contrast between the classical weak Huygens' principle and the classical strong Huygens' principle. Part of this work is joint with Mihai Tohaneanu and Jared Wunsch.
LOCATION:C304 Wells Hall
DTSTART:20220928T201000Z
DTEND:20220928T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29389
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29442@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Hecke algebra and Atkin-Lehner-Li’s theory
DESCRIPTION:Speaker\: Peikai Qi, MSU\r\nWe will use double closet to define Hecke algebra. And then we will have an review of Atkin-Lehner-Li’s theory without proof. If you miss the last seminar, it doesn’t matter. you can also understand most of this section.
LOCATION:C204A Wells Hall
DTSTART:20220929T190000Z
DTEND:20220929T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29442
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29393@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Hessian eigenvalues and hyperbolic polynomials
DESCRIPTION:Speaker\: Nam Le, Indiana University Bloomington\r\nHessian eigenvalues are natural nonlinear analogues of the classical Dirichlet eigenvalues. The Hessian eigenvalues and their corresponding eigenfunctions are expected to share many analytic and geometric properties (such as uniqueness, stability, max-min principle, global smoothness, Brunn-Minkowski inequality, etc) as their Dirichlet counterparts. In this talk, I will discuss these issues and some recent progresses in various geometric settings. The focus will be mostly on the case of the Monge-Ampere eigenfunctions and related degenerate equations. I will also explain the unexpected role of hyperbolic polynomials in our analysis. I will not assume any familiarity with these concepts.
LOCATION:C304 Wells Hall
DTSTART:20220929T201000Z
DTEND:20220929T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29393
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29439@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Introduction to Graph Algebras
DESCRIPTION:Speaker\: Lucas Hall, MSU\r\nWe introduce directed graphs and demonstrate how to generate a C*-algebra which reflects certain features of the graph. Time permitting, we will introduce two uniqueness theorems for their representations and explore a few of their consequences.
LOCATION:C517 Wells Hall
DTSTART:20221003T200000Z
DTEND:20221003T213000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29439
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29407@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Generalized wreath products and rigidity of their von Neumann algebras
DESCRIPTION:Speaker\: Bin Sun, University of Oxford\r\nWe construct the first positive examples to the Connes' Rigidity Conjecture, i.e., we construct groups $G$ with Kazhdan's property (T) such that if $H$ is a group with the same von Neumann algebra as $G$, then $H\cong G$. In this talk, I will focus on the group-theoretic side of this result and talk about how we applied geometric group theory to solve problems from von Neumann algebra. This is joint work with Ionut Chifan, Adrian Ioana, and Denis Osin.\r\n
LOCATION:C304 Wells Hall
DTSTART:20221004T150000Z
DTEND:20221004T155000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29407
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30445@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Assessment Modalities in gateway courses
DESCRIPTION:Speaker\: Round Table Discussion, MSU\r\n
LOCATION:C517 Wells Hall
DTSTART:20221004T170000Z
DTEND:20221004T180000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30445
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30447@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Knot lattice homology and the Gukov-Manolescu 2-variable series
DESCRIPTION:Speaker\: Peter Johnson, Michigan State University\r\nIn previous work of Akhmechet, Krushkal, and the speaker, a unification of lattice cohomology and the $\widehat{Z}$-invariant was established. Both theories are combinatorially defined invariants of plumbed 3-manifolds, but with quite different origins. Lattice cohomology, due to Némethi, is motivated by the study of normal surface singularities and is isomorphic to Heegaard Floer homology for plumbing trees. On the other hand, $\widehat{Z}$, due to Gukov-Pei-Putrov-Vafa, is a power series coming from a physical theory and is conjectured to recover quantum invariants of 3-manifolds at roots of unity. In this talk, I will discuss work in progress relating knot lattice homology and the Gukov-Manolescu 2-variable series, the knot theoretic counterparts to lattice homology and $\widehat{Z}$. This is joint work with Ross Akhmechet and Sunghyuk Park.
LOCATION:C304 Wells Hall
DTSTART:20221004T190000Z
DTEND:20221004T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30447
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30454@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Basics on Intersection Theory
DESCRIPTION:Speaker\: Ivan So\r\n
LOCATION:C517 Wells Hall
DTSTART:20221004T203000Z
DTEND:20221004T213000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30454
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29446@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Flow-firing processes
DESCRIPTION:Speaker\: Caroline Klivans, Brown University\r\nI will discuss a discrete non-deterministic flow-firing process for topological cell complexes. The process is a form of discrete diffusion; a flow is repeatedly diverted according to a discrete Laplacian. The process is also an instance of higher-dimensional chip-firing. I will motivate and introduce the system and then focus on two important features – whether or not the system is terminating and whether or not the system is confluent.
LOCATION:Online (virtual meeting)
DTSTART:20221005T190000Z
DTEND:20221005T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29446
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29392@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Polynuclear growth and the Toda lattice
DESCRIPTION:Speaker\: Konstantin Matetski, MSU\r\nPolynuclear growth is one of the basic models in the Kardar-Parisi-Zhang universality class, which describes a one-dimensional crystal growth. For a particular initial state, it describes the length of the longest increasing subsequence for uniformly random permutations (the problem first studied by S. Ulam). In my joint work with J. Quastel and D. Remenik we expressed the distribution functions of the polynuclear growth in terms of the solutions of the Toda lattice, one of the classical integrable systems. A suitable rescaling of the model yields a non-trivial continuous limit of the polynuclear growth (the KPZ fixed point) and the respective equations (Kadomtsev-Petviashvili).
LOCATION:C304 Wells Hall
DTSTART:20221005T201000Z
DTEND:20221005T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29392
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29435@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:1W-MINDS talk (passcode is the first prime number > 100).
DESCRIPTION:Speaker\: Weijie Su, University of Pennsylvania\r\nWhat Should a Good Deep Neural Network Look Like? Insights from a Layer-Peeled Model and the Law of Equi-Separation\r\n\r\n\r\nSee https://sites.google.com/view/minds-seminar/home\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221006T183000Z
DTEND:20221006T193000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29435
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30451@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Integral modular forms
DESCRIPTION:Speaker\: Jie Yang, MSU\r\nWe'll describe integral aspects of modular form theory, and discuss some applications.
LOCATION:C204A Wells Hall
DTSTART:20221006T190000Z
DTEND:20221006T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30451
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29263@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Exotic phenomena in 4-dimensional topology
DESCRIPTION:Speaker\: Lisa Piccirillo, Massachusetts Institute of Technology\r\nIn favorable circumstances, topological 4-manifolds and surfaces in them can be classified. In contrast, little is known about smooth 4-manifolds and smooth surfaces. Several of the hardest problems in 4-dimensional topology (eg. the Poincare conjecture) simply ask whether the topological classification fails in the smooth setting; such failures are called exotica. In this talk, I will discuss some historic and recent progress towards detecting exotic phenomena, and outline some promising approaches.
LOCATION:C304 Wells Hall
DTSTART:20221006T201000Z
DTEND:20221006T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29263
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30464@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Efficient Modewise Measurements for Compressive Sensing or Recovery of Tensor Data
DESCRIPTION:Speaker\: Cullen Haselby, MSU\r\nRecovery of sparse vectors and low-rank matrices from a small number of linear measurements is well-known to be possible under various model assumptions on the measurements. The key requirement on the measurement matrices is typically the restricted isometry property, that is, approximate orthonormality when acting on the subspace to be recovered. Among the most widely used random matrix measurement models are (a) independent subgaussian models and (b) randomized Fourier-based models, allowing for the efficient computation of the measurements.\r\n $\\$\r\nFor the now ubiquitous tensor data, direct application of the known recovery algorithms to the vectorized or matricized tensor is memory-heavy because of the huge measurement matrices to be constructed and stored. In this talk, we will discuss two different modewise measurement schemes and related recovery algorithms. These modewise operators act on the pairs or other small subsets of the tensor modes separately. They require significantly less memory than the measurements working on the vectorized tensor, and experimentally can recover the tensor data from fewer measurements and do not require impractical storage.\r\n$\\$\r\nThis will be a hybrid seminar and take place in C117 Wells Hall and via Zoom at https://msu.zoom.us/j/99426648081?pwd=ZEljM3BPUXg2MjVUMVM5TnlzK2NQZz09 .
LOCATION:C117 Wells Hall
DTSTART:20221010T170000Z
DTEND:20221010T180000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30464
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29445@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Ramification bounds for mod p étale cohomology via prismatic cohomology
DESCRIPTION:Speaker\: Pavel Čoupek, MSU\r\nLet $K/\bf{Q}_p$ be a local number field of absolute ramification index $e$, and let $X$ be a proper smooth $O_K$-scheme. I will discuss how one can obtain bounds on ramification of the mod $p$ Galois representations arising as the étale cohomology of (the geometric generic fiber of) $X$ in terms of $e$, the given prime $p>2$ and the cohomological degree $i$. The key tools for achieving this are the Breuil-Kisin and $A_{\rm inf}$-cohomology theories of Bhatt, Morrow and Scholze, and a series of conditions based on a criterion of Gee and Liu regarding crystallinity of the representation attached to a free Breuil-Kisin-Fargues $G_K$-module.
LOCATION:C304 Wells Hall
DTSTART:20221010T190000Z
DTEND:20221010T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29445
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29422@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Sp(4) stated skein algebras
DESCRIPTION:Speaker\: Vijay Higgins, Michigan State University\r\nSkein algebras are spanned by webs or links in a thickened surface subject to skein relations. When the skein relations are the Kauffman bracket relations associated to SL(2), they provide a diagrammatic way to encode cluster algebras, as shown by Muller, and also quantum groups, as shown by Costantino and Le.\r\nIn this talk, we will explore a construction of a basis for the stated skein algebra for Sp(4) which is built from Kuperberg's web relations along with extra skein relations along the boundary of the surface. We will use the basis to obtain results about the structure of the skein algebra, relating it to the quantum group associated to Sp(4). We will also recover Kuperberg's result about the Sp(4) web category.
LOCATION:C204A Wells Hall
DTSTART:20221010T190000Z
DTEND:20221010T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29422
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29440@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Graph algebras: universality, uniqueness, and ideal structure
DESCRIPTION:Speaker\: Lucas Hall, MSU\r\nWe illustrate various aspects of graph algebras introduced last week, including usage of the universal property, aspects of their representation theory, and ideals, pointing to relationships with the structure of the underlying graph.
LOCATION:C517 Wells Hall
DTSTART:20221010T200000Z
DTEND:20221010T213000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29440
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30448@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Diffusion for a Quantum Particle in a Lindbladian Environment with a Periodic Hamiltonian
DESCRIPTION:Speaker\: Jacob Gloe, MSU\r\nA quantum particle restricted to a lattice of points has been well studied in many different contexts. In the absence of disorder or environmental interaction, the particle simply undergoes ballistic transport for many suitable Hamiltonian operators. Recently, progress has been made on introducing a Lindbladian interaction term to the model, which drastically changes the dynamics in the large time limit. We prove that indeed diffusion is present in this context for an arbitrary periodic Hamiltonian. Additionally, we show that the diffusion constant is inversely proportional to the particles' coupling strength with its environment.\r\n
LOCATION:C304 Wells Hall
DTSTART:20221011T150000Z
DTEND:20221011T160000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30448
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29432@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Dimers, webs, and local systems
DESCRIPTION:Speaker\: Daniel Douglas, Yale\r\nFor a planar bipartite graph G equipped with a SLn-local system, we show that the determinant of the associated Kasteleyn matrix counts “n-multiwebs” (generalizations of n-webs) in G, weighted by their web-traces. We use this fact to study random n-multiwebs in graphs on some simple surfaces. Time permitting, we will discuss some relations to Fock-Goncharov theory. This is joint work with Rick Kenyon and Haolin Shi.
LOCATION:C304 Wells Hall
DTSTART:20221011T190000Z
DTEND:20221011T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29432
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30466@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Cycles and the Chow Ring
DESCRIPTION:Speaker\: Stan Halstead\r\nIntersections between varieties and subschemes can result in structures with many varying dimensions, which naturally leads us to consider something like a homology structure. The non-Hausdorff nature of the Zariski topology limits our ability to utilize algebraic topology, so we must first define cycles, the formal sum of subvarieties, to get something we can work with.
LOCATION:C517 Wells Hall
DTSTART:20221011T203000Z
DTEND:20221011T213000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30466
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29437@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:1W-MINDS talk (passcode is the first prime number > 100).
DESCRIPTION:Speaker\: Dustin Mixon, Ohio State University\r\nSee https://sites.google.com/view/minds-seminar/home\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221013T183000Z
DTEND:20221013T193000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29437
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29447@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Generalized recursive atom ordering and equivalence to CL-shellability
DESCRIPTION:Speaker\: Patricia Hersh, University of Oregon\r\nWhen Björner and Wachs introduced one of the main forms of lexicographic shellability, namely CL-shellability, they also introduced the notion of recursive atom ordering, and they proved that a finite bounded poset is CL-shellable if and only if it admits a recursive atom ordering. We generalize the notion of recursive atom ordering, and we prove that any such generalized recursive atom ordering may be transformed via a reordering process into a recursive atom ordering. We also prove that a finite bounded poset admits a generalized recursive atom ordering if and only if it is ``CC-shellable'' by way of a CC-labeling which is self-consistent in a certain sense. This allows us to conclude that CL-shellability is equivalent to self-consistent CC-shellability. As an application, we prove that the uncrossing orders, namely the face posets for stratified spaces of planar electrical networks, are dual CL-shellable. \r\n\r\nDuring this talk, we will review plenty of background on poset topology and specifically regarding the technique of lexicographic shellability. This is joint work with Grace Stadnyk\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221013T190000Z
DTEND:20221013T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29447
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30462@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Eigenalgebra
DESCRIPTION:Speaker\: Sgallova Ester , MSU\r\nEigenalgebra is a construction attaching to a family of commuting operators acting on some space or module that parameterizes the system of eigenvalue for some operators.
LOCATION:C204A Wells Hall
DTSTART:20221013T190000Z
DTEND:20221013T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30462
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29428@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Unique generalization properties of a dense set of classifiers based on one-dimensional random projections
DESCRIPTION:Speaker\: Evzenie Coupkova, Purdue\r\nThe generalization error of a classifier is related to the complexity of the set of functions among which the classifier is chosen. We study a family of low-complexity classifiers consisting of thresholding a random one-dimensional feature. The feature is obtained by projecting the data on a random line after embedding it into a higher-dimensional space parametrized by monomials of order up to k. More specifically, the extended data is projected n-times and the best classifier among those n, based on its performance on training data, is chosen. We show that this type of classifier is extremely flexible, as it is likely to approximate, to an arbitrary precision, any continuous function on a compact set as well as any Boolean function on a compact set that splits the support into measurable subsets. In particular, given full knowledge of the class conditional densities, the error of these low-complexity classifiers would converge to the optimal (Bayes) error as k and n go to infinity. On the other hand, if only a training dataset is given, we show that the classifiers will perfectly classify all the training points as k and n go to infinity. We also bound the generalization error of our random classifiers. In general, our bounds are better than those for any classifier with VC dimension greater than O (ln n) . In particular, our bounds imply that, unless the number of projections n is extremely large, there is a significant advantageous gap between the generalization error of the random projection approach and that of a linear classifier in the extended space. Asymptotically, as the number of samples approaches infinity, the gap persists for any such n. Thus, there is a potentially large gain in generalization properties by selecting parameters at random, rather than optimization.\r\n$\\$\r\nA preprint of this work can be found here: https://arxiv.org/abs/2108.06339\r\n$\\$\r\nThis will be a hybrid seminar and take place in C117 Wells Hall and via Zoom at https://msu.zoom.us/j/99426648081?pwd=ZEljM3BPUXg2MjVUMVM5TnlzK2NQZz09 .
LOCATION:C117 Wells Hall
DTSTART:20221017T170000Z
DTEND:20221017T180000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29428
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30469@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Rational torsion in modular Jacobians
DESCRIPTION:Speaker\: Preston Wake, MSU\r\nI will talk about Ogg's conjecture and its generalization. This is joint work with Ken Ribet (and should serve as an introduction to Ken's talk on Friday).
LOCATION:C304 Wells Hall
DTSTART:20221017T190000Z
DTEND:20221017T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30469
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30450@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Limiting Theorems for Discrete and Continuous Parameter Stationary and Ergodic Quantum Processes.
DESCRIPTION:Speaker\: Lubashan Pathirana, MSU\r\nA discrete parameter quantum process is represented by a sequence of quantum operations, which are completely positive maps that are trace non-increasing. Given a stationary and ergodic sequences of such maps, an ergodic theorem describing convergence to equilibrium for a general class of such processes was recently obtained by Movassagh and Schenker. Under irreducibility conditions we obtain a law of large numbers that describes the asymptotic behavior of the processes involving the Lyapunov exponent. Furthermore, a central limit type theorem is obtained under mixing conditions. In the continuous time parameter, a quantum process is represented by a double-indexed family of positive map valued random variables. For a stationary and ergodic family of such maps, we extend the results by Movassagh and Schenker to the continuous case.
LOCATION:C304 Wells Hall
DTSTART:20221018T150000Z
DTEND:20221018T160000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30450
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30467@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY: Cluster algebras and Nakajima's graded quiver varieties
DESCRIPTION:Speaker\: Li Li, Oakland University\r\nNakajima's graded quiver varieties are complex algebraic varieties associated with quivers. They are introduced by Nakajima in the study of representations of universal enveloping algebras of Kac-Moody Lie algebras, and can be used to study cluster algebras. In the talk, I will explain how to precisely locate the supports of the triangular basis of skew-symmetric rank 2 quantum cluster algebras by applying the decomposition theorem to various morphisms related to quiver varieties, thus prove a conjecture proposed by Lee-Li-Rupel-Zelevinsky in 2014.
LOCATION:C204A Wells Hall
DTSTART:20221018T163000Z
DTEND:20221018T173000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30467
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29418@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Families of contact structures and monopole Floer homology
DESCRIPTION:Speaker\: Juan Muñoz-Echániz, Columbia University\r\nThe contact invariant, defined by Kronheimer and Mrowka, is \r\nan element in the monopole Floer homology of a 3-manifold canonically \r\nattached to a contact structure. I will discuss how the contact \r\ninvariant places constraints on the topology of families of contact \r\nstructures, and how it can be used to detect non-trivial \r\ncontactomorphisms given by "Dehn twists" on spheres. The main new tool \r\nis a generalisation of the contact invariant to an invariant of \r\nfamilies of contact structures.\r\n
LOCATION:C304 Wells Hall
DTSTART:20221018T190000Z
DTEND:20221018T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29418
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30465@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:The KPZ fixed point.
DESCRIPTION:Speaker\: Konstatin Matetski, MSU\r\nThe KPZ universality class contains one-dimensional random growth models, which under quite general assumptions exhibit similar (non-Gaussian) scaling behavior. For special initial states, the limiting distributions surprisingly coincide with those from the random matrix theory. The physical explanation is that in the space of Markov processes, these models are all being rescaled to a universal fixed point. This scaling invariant fixed point was first characterized in joint work with Jeremy Quastel and Daniel Remenik. In our work, we found a surprising relation between random growing interfaces and the solutions of the classical integrable systems.
LOCATION:C405 Wells Hall
DTSTART:20221019T190000Z
DTEND:20221019T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30465
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29390@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Equilibria and stability in Vlasov-Maxwell equation
DESCRIPTION:Speaker\: Katherine Zhiyuan Zhang, Courant Institute, NYU\r\nWe present results on the stability of equilibria (time-independent solutions) of the Vlasov-Maxwell equation. In particular, linear stability criteria for certain classes of equilibria are discussed. We also give a result on the nonlinear stability of an initial-boundary value problem for the Vlasov-Poisson equation. \r\n\r\n**Note: speaker will present Virtually. Participants can join in person to view the presentation in C304, or through the Zoom link.**
LOCATION:C304 Wells Hall
DTSTART:20221019T201000Z
DTEND:20221019T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29390
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30470@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Eigenalgebra over field
DESCRIPTION:Speaker\: Pavel coupek , MSU\r\nWe move from the talks about general eigenalgebra to a special base field.
LOCATION:C204A Wells Hall
DTSTART:20221020T190000Z
DTEND:20221020T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30470
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29420@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:The Unreasonable Effectiveness of Elliptic Curves
DESCRIPTION:Speaker\: Ken Ribet, UC Berkeley\r\nIf a and b are integers that satisfy a simple nonvanishing\r\ncondition, the cubic equation y^2 = x^3 + ax + b defines an elliptic\r\ncurve over the field of rational numbers. Elliptic curves have been\r\nstudied for millennia and seem to occur all over the place in\r\nmathematics, physics and other sciences. In my talk, I'll explain how a\r\nspecific elliptic curve provides the solution to a surprisingly hard "brain\r\nteaser" that had a big run on social media a few years ago.
LOCATION:C304 Wells Hall
DTSTART:20221020T201000Z
DTEND:20221020T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29420
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29434@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Cyclotomic torsion points on abelian varieties over number fields
DESCRIPTION:Speaker\: Ken Ribet, UC Berkeley\r\nOver 40 years ago, I proved the finiteness of the group of cyclotomic torsion points on an abelian variety over a number field. (A torsion point is cyclotomic if its coordinates lie in the field obtained by\r\nadjoining all roots of unity to the base field.) If the abelian variety is one that we know well, and if the number field is the field of rational numbers, we can hope to determine explicitly the group of\r\nits cyclotomic torsion points. I will illustrate this theme in the situation studied by Barry Mazur in his landmark "Eisenstein ideal" article, i.e., that where the abelian variety is the Jacobian of the\r\nmodular curve $X_0(p)$.
LOCATION:C304 Wells Hall
DTSTART:20221021T190000Z
DTEND:20221021T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29434
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29396@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:On the irrationality of some algebraic varieties and their subvarieties
DESCRIPTION:Speaker\: Nathan Chen, Columbia University\r\nThe classical question of determining which varieties are rational has led to a huge amount of interest and activity. On the other hand, one can take on a complementary perspective - given a smooth projective variety whose nonrationality is known, how far is it from being rational? I will survey what is currently known, with an emphasis on hypersurfaces and complete intersections.
LOCATION:C304 Wells Hall
DTSTART:20221024T190000Z
DTEND:20221024T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29396
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30472@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Boundary Green's function and Minkowski content for SLE$_\kappa(\rho)$
DESCRIPTION:Speaker\: Dapeng Zhan, MSU\r\nWe prove the existence of the Minkowski content of the intersection of an SLE$_\kappa(\rho)$ curve with a real interval using the standard approach, which is to estimate the convergence rate of one-point and two-point boundary Green's functions of SLE$_\kappa(\rho)$. Then we show the existence of a conformally covariant measure called Minkowski content measure on the intersection of an SLE$_\kappa(\rho)$ curve with a half real line, which is closely related to the Minkowski content. Using the Minkowski content measure, we construct rooted and unrooted SLE$_\kappa(\rho)$ bubble measures, which are supported on loops and satisfy SLE$_\kappa(\rho)$-type domain Markov property.
LOCATION:C405 Wells Hall
DTSTART:20221026T190000Z
DTEND:20221026T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30472
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30468@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:A Study Of Homomesy On Permutations Using The FindStat Database
DESCRIPTION:Speaker\: Nadia Lafrenière, Dartmouth\r\nWe performed a systematic study of permutation statistics and\r\nbijective maps on permutations, looking for the homomesy phenomenon.\r\nHomomesy occurs when the average value of a statistic is the same on\r\neach orbit of a given map. The maps that exhibit homomesy include the\r\nLehmer code rotation, the reverse, the complement, and the\r\nKreweras complement, all of which have some geometric interpretations.\r\nThe statistics studied relate to familiar notions such as inversions,\r\ndescents, and permutation patterns, among others. Beside the many new\r\nhomomesy results, I’ll discuss our research method, in which we used\r\nSageMath to search the FindStat combinatorial statistics database to\r\nidentify potential instances of homomesy, and what this experiment\r\ntaught us about the maps themselves and the homomesy phenomenon at large.\r\nThis is joint work with Jennifer Elder, Erin McNicholas, Jessica Striker\r\nand Amanda Welch.\r\n\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221026T190000Z
DTEND:20221026T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30468
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30456@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:1W-MINDS talk (passcode is the first prime number > 100).
DESCRIPTION:Speaker\: Guanghui Lan, Georgia Institute of Technology\r\nSee https://sites.google.com/view/minds-seminar/home\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221027T183000Z
DTEND:20221027T193000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30456
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30474@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Eigenalgebra over field and over DVR
DESCRIPTION:Speaker\: Pavel coupek, MSU\r\nContinuation of previous talk. Following the eigenalgebra book, after considering eigenalgebra over field, if time allow, we will talks about eigenalgebra over dvr
LOCATION:C204A Wells Hall
DTSTART:20221027T190000Z
DTEND:20221027T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30474
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29384@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Hop on the left-regular band-wagon!
DESCRIPTION:Speaker\: Victor Reiner, University of Minnesota\r\nWe will give a gentle introduction to a class of finite semigroups\r\nbearing the cryptic name "left-regular bands" (LRBs). These LRBs show up, for example, in the combinatorics of reflection groups and hyperplane arrangements, in the analysis of mixing times for certain card-shuffling Markov chains, as well as in the space of phylogenetic trees.\r\n We focus on examples with large groups of symmetries that act on the semigroup algebra of the LRB. Here the well-understood LRB representation theory, together with some combinatorics, allow one to answer two invariant-theory questions: What is the structure of the invariant subalgebra, and how does it act on the whole semigroup algebra? \r\n This is based on joint work with Sarah Brauner and Patty Commins (arXiv:2206.11406).
LOCATION:C304 Wells Hall
DTSTART:20221027T201000Z
DTEND:20221027T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29384
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30481@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Cluster structures on braid varieties
DESCRIPTION:Speaker\: Linhui Shen, Michigan State University\r\nLet G be a complex simple group. Let $\beta$ be a positive braid whose Demazure product is the longest Weyl group element. The braid variety X($\beta$) generalizes many well known varieties, including positroid cells, open Richardson varieties, and double Bott-Samelson cells. We provide a concrete construction of the cluster structure on X($\beta$), using the weaves of Casals and Zaslow. We show that the coordinate ring of X($\beta$) is a cluster algebra, which confirms a conjecture of Leclerc as special cases. As an application, we show that X($\beta$) admits a natural Poisson structure and can be further quantized. If\r\ntime permits, I will explain several of its applications on representation theory and knot theory,\r\nincluding its connections with the Kazhdan-Lusztig R-polynomials and a geometric interpretation of the\r\nKhovanov-Rozansky homology (following the work of Lam-Speyer and Galashin-Lam). This talk is based on joint work with Roger Casals, Eugene Gorsky, Mikhail Gorsky, Ian Le, and Jose Simental (arXiv:2207.11607).
LOCATION:C304 Wells Hall
DTSTART:20221031T163000Z
DTEND:20221031T173000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30481
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30483@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Exemplar-Based Texture Synthesis: Past and Current Approaches
DESCRIPTION:Speaker\: Liping Yin, MSU\r\nIn this talk, we will give an overview of exemplar-based texture synthesis. For the first part of the talk, we will discuss a classical approach via matching statistics of wavelet coefficients and its shortcomings. In the second part of the talk, we will discuss more recent work using statistics of deep convolutional neural networks for more realistic texture synthesis.\r\n$\\$\r\nThis will be a hybrid seminar and take place in C117 Wells Hall and via Zoom at https://msu.zoom.us/j/99426648081?pwd=ZEljM3BPUXg2MjVUMVM5TnlzK2NQZz09 .
LOCATION:C117 Wells Hall
DTSTART:20221031T170000Z
DTEND:20221031T180000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30483
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29443@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Integral points in families of elliptic curves
DESCRIPTION:Speaker\: Stephanie Chan, UMich\r\nGiven an elliptic curve over a number field with its Weierstrass model, we can study the integral points on the curve. Taking an infinite family of elliptic curves and imposing some ordering, we may ask how often a curve has an integral point and how many integral points there are on average. We expect that elliptic curves with any non-trivial integral points are generally very sparse. In certain quadratic and cubic twist families, we prove that almost all curves contain no nontrivial integral points.
LOCATION:C304 Wells Hall
DTSTART:20221031T190000Z
DTEND:20221031T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29443
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30455@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Ballistic Transport for Limit-periodic Schrödinger Operators in One Dimension
DESCRIPTION:Speaker\: Giorgio Young, University of Michigan\r\nAbstract: In this talk, I will discuss some results on the transport properties of the class of limit-periodic continuum \r\nSchr\"odinger operators whose potentials are approximated exponentially quickly by a sequence of periodic functions. \r\nFor such an operator $H$, and $X_H(t)$ the Heisenberg evolution of the position operator, we show the limit of $\frac{1}{t}X_H(t)\psi$ as $t\to\infty$ exists and is \r\nnonzero for $\psi\ne 0$ belonging to a dense subspace of initial states which are sufficiently regular and of suitably rapid decay. \r\nThis is viewed as a particularly strong form of ballistic transport, and this is the first time it has been proven in a continuum almost periodic \r\nnon-periodic setting. In particular, this statement implies that for the initial states considered, the second moment grows quadratically in time.
LOCATION:C304 Wells Hall
DTSTART:20221101T150000Z
DTEND:20221101T160000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30455
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29433@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:On the 1-loop conjecture of fundamental shadow link complements
DESCRIPTION:Speaker\: Ka Ho Wong, Texas A&M\r\nThe 1-loop conjecture proposed by Dimofte and Garoufalidis suggests a simple and explicit formula to compute the adjoint twisted Reidemeister torsion of hyperbolic 3-manifolds with toroidal boundary in terms of the shape parameters of any ideal triangulation of the manifolds. In this talk, I will give a brief overview of the conjecture and present our recent result on the 1-loop conjecture for fundamental shadow link complements. This is a joint work with Tushar Pandey.
LOCATION:C304 Wells Hall
DTSTART:20221101T190000Z
DTEND:20221101T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29433
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30488@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Local rigidity of higher rank partially hyperbolic algebraic actions
DESCRIPTION:Speaker\: Zhenqi Wang, Michigan State University\r\nWe give a complete solution to the local classification program of higher rank partially hyperbolic algebraic actions. We show $C^\infty$ local rigidity of abelian ergodic algebraic actions for symmetric space examples, twisted symmetric space examples and automorphisms on nilmanifolds. The method is a combination of representation theory, harmonic analysis and a KAM iteration. A striking feature of the method is no specific information from representation theory is needed. It is the first time local rigidity for non-accessible partially hyperbolic actions has ever been obtained other than torus examples. Even for Anosov actions, our results are new: it is the first time twisted spaces with non-abelian nilradical have been treated in the literature. \r\n
LOCATION:A136 Wells Hall
DTSTART:20221101T190000Z
DTEND:20221101T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30488
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30482@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:FORMULAS FOR THE DIVERGENCE OPERATOR IN ISONORMAL GAUSSIAN SPACE
DESCRIPTION:Speaker\: Shlomo Levental, MSU\r\nIn this joint paper with P. Vellaisamy, we first derive some explicit formulas for the computation \r\nof the n-th order divergence operator in Malliavin calculus in the one-dimensional case. We then extend these results to the case of isonormal Gaussian space. Our results generalize some of the known results for the divergence operator. Our approach in deriving the formulas is new and simple.
LOCATION:C405 Wells Hall
DTSTART:20221102T190000Z
DTEND:20221102T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30482
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30478@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:A Pentagonal Number Theorem for Tribone Tilings
DESCRIPTION:Speaker\: James Propp, University of Massachusetts, Lowell\r\nConway and Lagarias used combinatorial group theory to show that certain\r\nroughly triangular regions in the hexagonal grid cannot be tiled by the\r\nshapes Thurston later dubbed tribones. The ideas of Conway, Lagarias, and\r\nThurston have found many applications in the study of tilings in the plane.\r\nToday I'll discuss a two-parameter family of roughly hexagonal regions in\r\nthe hexagonal grid I call benzels. A variant of Gauss’ shoelace formula\r\nallows one to compute the signed area (aka algebraic area) enclosed by a\r\nclosed polygonal path, and by “twisting” the formula one can compute the\r\nvalues of the Conway-Lagarias invariant for all benzels. It emerges that the\r\n(a,b)-benzel can be tiled by tribones if and only if a and b are the paired\r\npentagonal numbers k(3k+1)/2, k(3k-1)/2. This is joint work with Jesse Kim.\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221102T190000Z
DTEND:20221102T195000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30478
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30484@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Escapism in Math: The Mathematics of Escapes
DESCRIPTION:Speaker\: Christopher Potvin, MSU\r\nAbstract: There comes a time in every mathematician's life when they are detained by an evil dictator or warden with a soft spot for riddles. Fortunately for us, these riddles are often rooted in simple mathematics. This talk will prepare you for that inevitable occurrence by going over the mathematics involved in several prominent riddles. Along the way, we'll pick up some tricks of the trade that you can use when facing a logic puzzle to make an escape of your own.
LOCATION:C517 Wells Hall
DTSTART:20221102T210000Z
DTEND:20221102T220000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30484
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30475@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Model Invariants and Functional Regularization
DESCRIPTION:Speaker\: Dr. Harvey Stein, Senior VP, Labs Group, Two Sigma\r\nWhen modeling data, we would like to know that our models are extracting facts about the data itself, and not about something arbitrary, like the order of the factors used in the model-ing. Formally speaking, this means we want the model to be invariant with respect to certain transformations. Here we look at different models and the nature of their invariants. We find that regression, MLE and Bayesian estimation all are invariant with respect to linear transformations, whereas regularized regressions have a far more limited set of invariants. As a result, regularized regressions produce results that are less about the data itself and more about how it is parameterized. To correct this, we propose an alternative expression of regularization which we call functional regularization. Ridge regression and lasso can be recast in terms of functional regularization, as can Bayesian estimation. But functional regularization preserves model invariance, whereas ridge and lasso do not. It is also more flexible, easier to understand, and can even be applied to non-parametric models.
LOCATION:C304 Wells Hall
DTSTART:20221103T183000Z
DTEND:20221103T193000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30475
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30457@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:1W-MINDS talk (passcode is the first prime number > 100).
DESCRIPTION:Speaker\: Alex Townsend , Cornell University\r\nSee https://sites.google.com/view/minds-seminar/home\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221103T183000Z
DTEND:20221103T193000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30457
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30486@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Eigenalgebras over DVR, continued
DESCRIPTION:Speaker\: Keping Huang, MSU\r\n
LOCATION:C204A Wells Hall
DTSTART:20221103T190000Z
DTEND:20221103T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30486
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29386@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Representations of reductive groups over local fields
DESCRIPTION:Speaker\: Tasho Kaletha, University of Michigan\r\nThe pioneering work of Langlands has established the theory of reductive algebraic groups and their representations as a key part of modern number theory. I will survey classical and modern results in the representation theory of reductive groups over local fields (the fields of real, complex, or p-adic numbers, or of Laurent series over finite fields) and discuss how they relate to Langlands' ideas, as well as to the various reflections of the basic mathematical idea of symmetry in arithmetic and geometry.
LOCATION:C304 Wells Hall
DTSTART:20221103T201000Z
DTEND:20221103T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29386
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30476@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Current Issues in Financial Risk Management
DESCRIPTION:Speaker\: Dr. Harvey Stein, Senior VP, Labs Group, Two Sigma\r\nInnovations and changes in financial markets do not come without\r\nrisks. We will discuss some recent innovations and changes and\r\ndiscuss their implications for risk management, such as the risks\r\nassociated with cryptocurrency, and the impact on finance of\r\nmachine learning.
LOCATION:3202 STEM
DTSTART:20221103T220000Z
DTEND:20221104T000000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30476
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30473@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Determinantal inequalities for totally positive matrices
DESCRIPTION:Speaker\: Daniel Soskin, University of Notre Dame\r\nTotally positive matrices are matrices in which each minor is positive. Lusztig extended the notion to reductive Lie groups. He also proved that specialization of elements of the dual canonical basis in representation theory of quantum groups at q=1 are totally non-negative polynomials. Thus, it is important to investigate classes of functions on matrices that are positive on totally positive matrices. I will discuss two sourses of such functions. One has to do with multiplicative determinantal inequalities (joint work with M.Gekhtman). Another deals with majorizing monotonicity of symmetrized Fischer's products which are known for hermitian positive semidefinite case which brings additional motivation to verify if they hold for totally positive matrices as well (joint work with M.Skandera). The main tools we employed are network parametrization, Temperley-Lieb and monomial trace immanants.
LOCATION:C304 Wells Hall
DTSTART:20221107T173000Z
DTEND:20221107T183000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30473
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30492@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Ensemble Clustering Methods in Transcriptomics Data
DESCRIPTION:Speaker\: Yuta Hozumi, MSU\r\nTranscriptomic data, more specifically single cell RNA sequencing (scRNA-seq), is an emerging field in biology that is used to obtain molecular understanding of cells. Analyzing scRNA-seq gives insight to protein and gene regulatory networks, protein expression and diseases. In this talk, I will present ensemble clustering methods used to find clusters in scRNA-seq data, which can then be used for further analysis into differential gene expression, cell trajectory and cell-cell communication.\r\n$\\$\r\nThis will be a hybrid seminar and take place in C117 Wells Hall and via Zoom at https://msu.zoom.us/j/99426648081?pwd=ZEljM3BPUXg2MjVUMVM5TnlzK2NQZz09 .
LOCATION:C117 Wells Hall
DTSTART:20221107T180000Z
DTEND:20221107T190000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30492
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30477@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:RTG Seminar: Quantum and hyperbolic invariants of knots (Introductory talk)
DESCRIPTION:Speaker\: Calvin McPhail-Snyder , Duke University\r\nThis talk consists of two related but distinct parts, and should be accessible if you know some algebraic topology and/or differential geometry. The first part is about quantum invariants: I will sketch how to compute the colored Jones polynomials of a knot and discuss their origin in representation theory. The second part is about hyperbolic geometry: I will discuss the basics of hyperbolic knot theory and explain how to compute hyperbolic structures and their volumes using ideal triangulations. The goal is to motivate the volume conjecture discussed in my main talk, which relates the colored Jones polynomials to the hyperbolic volume.
LOCATION:C304 Wells Hall
DTSTART:20221107T190000Z
DTEND:20221107T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30477
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29399@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Kuznetsov components of some Fano fourfolds
DESCRIPTION:Speaker\: Qingjing Chen, University of California Santa Barbara\r\nKuznetsov component A_X of an algebraic variety X is defined to be the right orthogonal of some exceptional collection in the bounded derived category of X. When X is a cubic fourfold or Gushel Mukai fourfold, A_X is a noncommutative K3 surface in the sense that its Serre functor is given by "shifting by 2". Whether or not A_X is equivalent to the bounded derived category of an actual K3 surface is believed to be related to the rationality of the variety X , therefore it has received extensive studies. Yet not many studies seem to answer the question of when the Kuznetsov component of a cubic fourfold is equivalent to that of a Gushel Mukai fourfold, we believe that the answer of this question should be interesting for it will give a part of "Torelli theorem for noncommutative K3 surfaces". In this talk, I will present some partial results which address the previous question.
LOCATION:C304 Wells Hall
DTSTART:20221107T200000Z
DTEND:20221107T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29399
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30489@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Free transport, I
DESCRIPTION:Speaker\: Brent Nelson, MSU\r\nIn operator algebras, specifically free probability, free transport is a technique for producing state-preserving isomorphisms between C* and von Neumann algebras that was developed by Guionnet and Shlyakhtenko in their 2014 Inventiones paper. The inspiration for their work comes from the field of optimal transport, specifically work of Brenier from 1991 who showed that under very mild assumptions one can push forward a probability measure on $\mathbb{R}^n$ to the Gaussian measure. In the non-commutative case, Guionnet and Shlyakhtenko showed that if $x_1,\ldots, x_n$ are self-adjoint operators in a tracial von Neumann algebra $(M,\tau)$ whose distribution satisfies an "integration-by-parts" formula up to a small perturbation, then these operators generate a copy of the free group factor $L(\mathbb{F}_n)$. In this series of talks, I will give an overview of their proof, discuss some applications of their result, and survey the current state of free transport theory.
LOCATION:C517 Wells Hall
DTSTART:20221107T210000Z
DTEND:20221107T223000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30489
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29411@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Hyperbolic tensor networks and the volume conjecture
DESCRIPTION:Speaker\: Calvin McPhail-Snyder , Duke University\r\nQuantum invariants of links like the colored Jones polynomial (which arise from the quantum Chern-Simons theory of Witten-Reshetikhin-Turaev) have a purely algebraic construction in terms of the representation theory of quantum groups. Despite this algebraic nature they appear to be connected to geometry: a class of related volume conjectures assert that their semi-classical asymptotics determine geometric invariants like the hyperbolic volume. To better understand these conjectures a number of authors have studied ways to twist quantum invariants by geometric data. In particular, Blanchet, Geer, Patureau-Mirand, and Reshetikhin recently defined quantum holonomy invariants depending on a link in S^3 and a flat 𝔰𝔩₂ connection on its complement. Their construction uses certain unusual cyclic modules of quantum 𝔰𝔩₂. For technical reasons the invariants are quite difficult to compute. In this talk (based on joint work with Nicolai Reshetikhin) I will explain how to effectively compute them using hyperbolic tensor networks constructed from quantum dilogarithms. Our construction reveals deep connections with hyperbolic geometry and suggests a way to break the Kashaev-Murakami-Murakami volume conjecture into two simpler pieces.
LOCATION:C304 Wells Hall
DTSTART:20221108T200000Z
DTEND:20221108T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29411
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30491@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Limiting Theorems for Compositions of Stationary and Ergodic Random Maps With Applications in Quantum Processes
DESCRIPTION:Speaker\: Lubashan Pathirana Karunarathna, MSU\r\nA discrete parameter quantum process is represented by a sequence of quantum operations, which are completely positive maps that are trace non-increasing. Given a stationary and ergodic sequence of such maps, an ergodic theorem describing convergence to equilibrium for a general class of such processes was recently obtained by Movassagh and Schenker. Under irreducibility conditions, we obtain a law of large numbers that describes the asymptotic behavior of the processes involving the Lyapunov exponent. Furthermore, a central limit-type theorem is obtained under mixing conditions. These results do not require the sequences of quantum operations that describe the quantum process to be trace non-increasing and hence can be applied to a larger class of compositions of random positive maps. In the continuous-time parameter, a quantum process is represented by a double-indexed family of positive map-valued random variables. For a stationary and ergodic family of such maps, we extend the results by Movassagh and Schenker to the continuous case.
LOCATION:C405 Wells Hall
DTSTART:20221109T200000Z
DTEND:20221109T205000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30491
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29379@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Buffon's needle problem for a random planar disk-like Cantor set
DESCRIPTION:Speaker\: Dimitris Vardakis, MSU\r\nThe Favard length of the planar $1/4$-corner Cantor set is $0$. Estimates exists about the rate with which the Favard length of the previous steps goes to $0$, but the exact rate of decay is unknown. However, if one considers a random construction of the $1/4$-corner Cantor set, things might seem better. In fact, Peres and Solomyak showed that the rate of decay for the average Favard length for the random $1/4$-corner Cantor set is of order exactly $1/n$. We show that the rate of decay for a random disk-like analogue has again order $1/n$. This suggests that any ``reasonable'' random Cantor set of positive and finite length might decay at the same rate.
LOCATION:C304 Wells Hall
DTSTART:20221109T211000Z
DTEND:20221109T220000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29379
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30490@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Classical modular symbols
DESCRIPTION:Speaker\: Keping Huang, MSU\r\n
LOCATION:C204A Wells Hall
DTSTART:20221110T200000Z
DTEND:20221110T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30490
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30480@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Super Cluster Algebras from Surfaces
DESCRIPTION:Speaker\: Nicholas Ovenhouse, Yale University\r\nOne of the most well-known examples of a cluster structure comes from Penner's lambda-length coordinates on the decorated Teichmuller space of a surface. In 2019, Penner and Zeitlin defined a super-manifold generalizing the decorated Teichmuller space, which involves new anti-commuting variables. I wall talk about some recent work with Gregg Musiker and Sylvester Zhang, where we showed that the coordinates on the decorated super Teichmuller space have many of the nice properties associated to a cluster structure, such as a kind of Laurent phenomenon, positivity, and some interesting combinatorial interpretations of the Laurent expressions, involving double dimer covers of certain graphs.
LOCATION:C304 Wells Hall
DTSTART:20221114T173000Z
DTEND:20221114T183000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30480
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31497@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Wavelets, the Scattering Transform, and Generalizations
DESCRIPTION:Speaker\: Albert Chua, MSU\r\nIn this talk, we give an overview of some basic properties of wavelets. We then introduce the Windowed Scattering Transform and go over stability and invariance properties that make it desirable as a feature extractor. Finally, we provide a generalization of the Windowed Scattering Transform that is translation invariant and discuss other stability and invariance properties of our generalized Scattering Transform. \r\n$\\$\r\nThis will be a hybrid seminar and take place in C117 Wells Hall and via Zoom at https://msu.zoom.us/j/99426648081?pwd=ZEljM3BPUXg2MjVUMVM5TnlzK2NQZz09 .
LOCATION:C117 Wells Hall
DTSTART:20221114T180000Z
DTEND:20221114T190000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31497
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30495@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Animating Mathematical Concepts…(and the learning of teachers, students, and researchers)
DESCRIPTION:Speaker\: Higinio Dominguez, MSU, Tina Haselius, Teacher, Sofia Abreu, MSU, Melvin Peralta, MSU\r\nMathematics education research is overwhelmingly assimilationist in its desire\r\nto change people, teachers, students, researchers, instead of changing the mathematics. In this teaching-research collaboration, one teacher (Tina Haselius), two graduate research assistants (Sofía Abreu and Melvin Peralta), and one mathematics education researcher (Higinio Dominguez) will share their emerging experiences learning how to animate mathematical concepts. While one key goal in our collaboration has been to resist the violence of trying to change, assimilate, and colonize learners, the process of animating mathematical concepts has, in beautiful and nonviolent ways, allowed us to experience change in and among ourselves as we learn to (co)respond to the animacy and agency of the mathematical concepts that we set out to animate in our teaching-research group.
LOCATION:115 Erickson Hall
DTSTART:20221114T183000Z
DTEND:20221114T193000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30495
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29394@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Finite order birational automorphisms of Fano hypersurfaces
DESCRIPTION:Speaker\: Lena Ji, University of Michigan\r\nThe birational automorphism group is a natural birational invariant associated to an algebraic variety. In this talk, we study the specialization homomorphism for the birational automorphism group. As an application, building on work of Kollár and of Chen–Stapleton, we show that a very general n-dimensional complex hypersurface X of degree ≥ 5⌈(n+3)/6⌉ has no finite order birational automorphisms. This work is joint with Nathan Chen and David Stapleton.
LOCATION:C304 Wells Hall
DTSTART:20221114T200000Z
DTEND:20221114T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29394
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30496@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Free transport, II
DESCRIPTION:Speaker\: Brent Nelson, MSU\r\nIn operator algebras, specifically free probability, free transport is a technique for producing state-preserving isomorphisms between C* and von Neumann algebras that was developed by Guionnet and Shlyakhtenko in their 2014 Inventiones paper. The inspiration for their work comes from the field of optimal transport, specifically work of Brenier from 1991 who showed that under very mild assumptions one can push forward a probability measure on $\mathbb{R}^n$ to the Gaussian measure. In the non-commutative case, Guionnet and Shlyakhtenko showed that if $x_1,\ldots, x_n$ are self-adjoint operators in a tracial von Neumann algebra $(M,\tau)$ whose distribution satisfies an "integration-by-parts" formula up to a small perturbation, then these operators generate a copy of the free group factor $L(\mathbb{F}_n)$. In this series of talks, I will give an overview of their proof, discuss some applications of their result, and survey the current state of free transport theory.
LOCATION:C517 Wells Hall
DTSTART:20221114T210000Z
DTEND:20221114T223000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30496
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29430@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Symmetric link homology
DESCRIPTION:Speaker\: Louis-Hadrien Robert, Université Clermont Auvergne\r\nIn this talk I will detail a construction of symmetric link\r\nhomology. In particular, this provides a non-trivial categorification of\r\n1 and a finite dimensional categorification of the colored Jones\r\npolynomial and a new categorification of the Alexander polynomial. I\r\nwill also explain how this relates to the triply graded homology and\r\nknot Floer homology.
LOCATION:Online (virtual meeting)
DTSTART:20221115T200000Z
DTEND:20221115T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29430
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30497@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Coset lattices, invariable generation of simple groups, and a problem on binomial coefficients
DESCRIPTION:Speaker\: John Shareshian, Washington University\r\nIn joint work with Russ Woodroofe, we showed that the order complex of the poset of all cosets of all proper subgroups of a finite group, ordered by inclusion, has noncontractible order complex using Smith Theory. A key part of our proof involves invariable generation of finite groups: two subsets $S,T$ of a group $G$ generate $G$ invariably if, for every $g,h \in G$, $g^{-1}Sg$ and $h^{-1}Th$ together generate $G$. It remains open whether the alternating group $A_n$ can be generated invariably by $\{s\}$ and $\{t\}$ with both $s,t$ having prime power order. This question is closely related to a (still open) question about prime divisors of binomial coefficients. I will discuss all of this, along with current work joint with Bob Guralnick and Russ Woodroofe about invariable generation of arbitrary simple groups by two elements of prime or prime power order.
LOCATION:Online (virtual meeting)
DTSTART:20221116T200000Z
DTEND:20221116T205000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30497
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29444@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Energy decay for the damped wave equation
DESCRIPTION:Speaker\: Perry Kleinhenz, MSU\r\nThe damped wave equation models the behavior of vibrating systems exposed to some damping force, which causes the total energy to decay. In this talk, I will discuss classical results that give upper and lower bounds on decay, based on the dynamics of the geodesic flow and the support of the damping. I will discuss recent generalizations of these results to time dependent, unbounded, or anisotropic damping. \r\n\r\n(Note location: this talk will be held in C517 due to hiring meeting in C304.)
LOCATION:C517 Wells Hall
DTSTART:20221116T211000Z
DTEND:20221116T220000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29444
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30458@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:1W-MINDS talk (passcode is the first prime number > 100).
DESCRIPTION:Speaker\: Wei Zhu , University of Massachusetts Amherst\r\nSee https://sites.google.com/view/minds-seminar/home\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221117T193000Z
DTEND:20221117T203000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30458
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31496@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Modular symbols and modular forms
DESCRIPTION:Speaker\: Jie Yang\r\nWe will define modular symbols and discuss its relation with modular forms.
LOCATION:C204A Wells Hall
DTSTART:20221117T200000Z
DTEND:20221117T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31496
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31498@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Long Range Constraints for Neural Texture Synthesis Using Sliced Wasserstein Loss
DESCRIPTION:Speaker\: Liping Yin, MSU\r\nIn the past decade, exemplar-based texture synthesis algorithms have seen strong gains in performance by matching statistics of deep convolutional neural networks. However, these algorithms require regularization terms or user-added spatial tags to capture long range constraints in images. Thus, we propose a new set of statistics for exemplar based texture synthesis based on Sliced Wasserstein Loss and create a multi-scale algorithm to synthesize textures without any regularization terms or user-added spatial tags. Lastly, we study the ability of our proposed algorithm to capture long range constraints in images and compare our results to other exemplar-based neural texture synthesis algorithms.\r\n$\\$\r\nThis will be a hybrid seminar and take place in C117 Wells Hall and via Zoom at https://msu.zoom.us/j/99426648081?pwd=ZEljM3BPUXg2MjVUMVM5TnlzK2NQZz09 .
LOCATION:C117 Wells Hall
DTSTART:20221121T180000Z
DTEND:20221121T190000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31498
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31501@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Modular Stone-von Neumann Theorems
DESCRIPTION:Speaker\: Lucas Hall, MSU\r\nI’ll talk about C*-modules and representations on them, developing a loose parallel with the Hilbert space case. For specialized C*-modules, much can be said, and a classification of these modules suggests a vast generalization of the Stone-von Neumann Theorem which accommodates all of the data of generalized C*-dynamical systems.
LOCATION:C517 Wells Hall
DTSTART:20221121T210000Z
DTEND:20221121T223000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31501
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31499@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:TBD
DESCRIPTION:Speaker\: Rolando Ramos, MSU\r\nThis will be a hybrid seminar and take place in C117 Wells Hall and via Zoom at https://msu.zoom.us/j/99426648081?pwd=ZEljM3BPUXg2MjVUMVM5TnlzK2NQZz09 .
LOCATION:C117 Wells Hall
DTSTART:20221128T180000Z
DTEND:20221128T190000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31499
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30449@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:The eigencurve over the boundary of the weight space
DESCRIPTION:Speaker\: Zijian Yao, University of Chicago\r\nThe eigencurve is a rigid analytic curve that $p$-adically interpolates eigenforms of finite slope. The global geometry of the eigencurve is somewhat mysterious. However, over the boundary, it is predicted to behave rather nicely (by the so-called Halo conjecture). This conjecture has been studied by Liu--Wan--Xiao for definite quaternion algebras. In this talk, we will report on some work in progress on this conjecture in the case of $\rm{GL}(2)$. If time permits, we will discuss some generalizations towards groups beyond $\rm{GL}(2)$. This is partially joint with H. Diao.
LOCATION:C304 Wells Hall
DTSTART:20221128T200000Z
DTEND:20221128T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30449
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29441@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:An Introduction to K-theory
DESCRIPTION:Speaker\: Matthew Lorentz, MSU\r\nBased on the work of Grothendieck, in the 1960's Atiyah and Hirzebruch developed K-theory as a tool for algebraic geometry. Adapted to the topological setting K-theory can be regarded as the study of a ring generated by vector bundles. In the 1970's it was introduced as a tool in C*-algebras. C*-algebras are often considered to be "noncommutative topology", additionally they are an algebra over the complex numbers. In this setting the algebraic and topological definitions of K-theory overlap giving us a powerful tool. Essential for the Elliott classification program, for certain classes of C*-algebras, K-theory is a complete invariant. K-theory is also a natural setting for higher index theory.\r\n\r\nWe will begin by looking at different types of equivalence for projections. Then we will build a monoid where these types of equivalences are equivalent. We then use the Grothendieck construction to turn our monoid into an abelian group. This group is called the $K_0$ group of our algebra and can be thought of as the "connected components" of projections in our C*-algebra.\r\n\r\nNext, in a similar manner, we construct the $K_1$ group using unitaries from our C*-algebra. \r\nOnce we have the $K_0$ and $K_1$ groups we will discuss Bott periodicity and the six-term exact sequence, a tool used to calculate K-theory.
LOCATION:C517 Wells Hall
DTSTART:20221128T210000Z
DTEND:20221128T223000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29441
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29448@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Mapping class groups and dense conjugacy classes
DESCRIPTION:Speaker\: Justin Lanier, University of Chicago\r\nI’ll start by introducing infinite-type surfaces—those with infinite genus or infinitely many punctures—and the emerging study of their mapping class groups. One difference from the finite-type setting is that these mapping class groups come with natural non-discrete topologies. I’ll discuss joint work with Nick Vlamis where we fully characterize which surfaces have mapping class groups with dense conjugacy classes, so that there exists an element that well approximates every mapping class, up to conjugacy.
LOCATION:Online (virtual meeting)
DTSTART:20221129T200000Z
DTEND:20221129T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29448
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31502@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Decorated character varieties and their quantizations from factorization homology
DESCRIPTION:Speaker\: Gus Schrader, Northwestern University\r\n I will report on joint work with D. Jordan, I. Le and A. Shapiro in which we construct categorical invariants of decorated surfaces using the stratified factorization homology of Ayala, Francis and Tanaka, together with the representation theory of quantum groups. The categories we obtain can be regarded as `quantizations' of the categories of quasicoherent sheaves on the stacks of decorated local systems on surfaces, and satisfy strong functoriality and locality properties reminiscent of those of a TQFT. I will give an overview of their construction, and explain how to recover Fock-Goncharov-Shen's cluster quantizations of related moduli spaces within this framework.
LOCATION:C204A Wells Hall
DTSTART:20221129T210000Z
DTEND:20221129T220000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31502
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31503@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Multiplying quantum Schubert polynomials using combinatorics
DESCRIPTION:Speaker\: Laura Hernando Colmenarejo, North Carolina State University\r\nSchubert polynomials are a very interesting family of polynomials in algebraic geometry due to their relation with the cohomology of the flag variety. Moreover, they are also very interesting from a combinatorial point of view because they can be considered generalizations of Schur functions. In this talk, we will talk about how to multiply a Schubert polynomial by a Schur function indexed by a hook and how we can extend this multiplication to the quantum world. This is a current work with C. Benedetti, N. Bergeron, F. Saliola, and F. Sottile.
LOCATION:Online (virtual meeting)
DTSTART:20221130T200000Z
DTEND:20221130T205000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31503
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30494@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Characteristics of High School Mathematics Lessons that Increase Opportunities for Captivation
DESCRIPTION:Speaker\: Leslie Dietiker, Boston University\r\nWhy do some high school mathematics lessons captivate high school students and others not? This study explores this question by comparing how the content unfolds in the lessons that students rated highest with respect to their aesthetic affordances (e.g., using terms like “intriguing”, “surprising”) with those the same students rated lowest with respect to their aesthetic affordances (e.g., “just ok”, “dull”). Using a framework that interprets the unfolding content across a lesson as a mathematical story, we identified characteristics of lessons that provoked curiosity or enabled surprise. This talk will explain the methodological approach to studying this question, as well as share the lesson characteristics that related strongly to student experience. These findings point to the characteristics of future lesson designs that could enable more students to experience curiosity and wonder in secondary mathematics classrooms. Also on Zoom: https://msu.zoom.us/j/98171049554 Passcode: GOGREEN
LOCATION:252 EH
DTSTART:20221130T200000Z
DTEND:20221130T213000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30494
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30485@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:1W-MINDS talk (passcode is the first prime number > 100).
DESCRIPTION:Speaker\: Zhaoran Wang, Northwestern University\r\nSee https://sites.google.com/view/minds-seminar/home\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221201T193000Z
DTEND:20221201T203000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30485
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31500@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Classic modular symbol over complex field
DESCRIPTION:Speaker\: Peikai Qi, MSU\r\nWe will move from the classic modular symbol form to modular symbol over complex field. And we will use a lot of theorem from previous chapter as black box.
LOCATION:C204A Wells Hall
DTSTART:20221201T200000Z
DTEND:20221201T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31500
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31506@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Exchange Program REU Final Presentations
DESCRIPTION:Speaker\: Our undergraduate research teams!\r\nExchange Program REU Final Presentations\r\nSpeakers: Our undergraduate research teams!\r\nTitle: See the program, which includes descriptions of the research projects\r\nDate: Friday December 2, 2022\r\nTime: 6:30 p.m. – 9:45 p.m.\r\nhttps://msu.zoom.us/j/92801969144\r\nMeeting ID: 928 0196 9144\r\nPasscode: 112358\r\n
LOCATION:C304 Wells Hall
DTSTART:20221202T233000Z
DTEND:20221203T024500Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31506
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30479@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:TBA
DESCRIPTION:Speaker\: Alberto Takase, MSU\r\nTBA
LOCATION:C517 Wells Hall
DTSTART:20221205T210000Z
DTEND:20221205T223000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30479
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30463@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:TBA
DESCRIPTION:Speaker\: Ekaterina Shchetka, University of Michigan\r\n
LOCATION:C304 Wells Hall
DTSTART:20221206T160000Z
DTEND:20221206T170000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30463
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31508@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Boundary rigidity and filling minimality via the barycenter method
DESCRIPTION:Speaker\: Yuping Ruan, University of Michigan\r\nA compact manifold with a smooth boundary is boundary rigid if its boundary and boundary distance function uniquely determine its interior up to boundary preserving isometries. Under certain natural conditions, the notion of boundary rigidity is closely related to Gromov's filling minimality. In this talk, we will first give a brief overview of Burago-Ivanov's approach to prove filling minimality and boundary rigidity for almost Euclidean and almost real hyperbolic metrics. Then we will explain how we generalize their results to regions in a rank-1 symmetric space equipped with an almost symmetric metric. We will also explain the relations to Besson-Courtois-Gallot's barycenter constructions used in their celebrated volume entropy rigidity theorem.
LOCATION:A136 Wells Hall
DTSTART:20221206T190000Z
DTEND:20221206T200000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31508
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30446@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:TBA
DESCRIPTION:Speaker\: Cameron Gates Rudd, Max Planck Institute, Bonn\r\nTBA
LOCATION:Online (virtual meeting)
DTSTART:20221206T200000Z
DTEND:20221206T210000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30446
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-31507@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:Enriched toric $[\vec{D}]$-partitions
DESCRIPTION:Speaker\: Jinting Liang, Michigan State University\r\nIn this talk I will discuss the theory of enriched toric $[\vec{D}]$-partitions. Whereas Stembridge's enriched $P$-partitions give rises to the peak algebra which is a subring of the ring of quasi-symmetric functions QSym, our enriched toric $[\vec{D}]$-partitions will generate the cyclic peak algebra which is a subring of cyclic quasi-symmetric functions cQSym. In the same manner as the peak set of linear permutations appears when considering enriched $P$-partitions, the cyclic peak set of cyclic permutations plays an important role in our theory.
LOCATION:Online (virtual meeting)
DTSTART:20221207T200000Z
DTEND:20221207T205000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=31507
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-30459@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:1W-MINDS talk (passcode is the first prime number > 100).
DESCRIPTION:Speaker\: Rongjie Lai , Rensselaer Polytechnic Institute\r\nSee https://sites.google.com/view/minds-seminar/home\r\n
LOCATION:Online (virtual meeting)
DTSTART:20221208T193000Z
DTEND:20221208T203000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=30459
END:VEVENT
BEGIN:VEVENT
UID:20221202T001943-29431@math.msu.edu
DTSTAMP:20221202T001943Z
SUMMARY:TBA
DESCRIPTION:Speaker\: Renaud Requipas, NYU\r\n
LOCATION:C304 Wells Hall
DTSTART:20221212T160000Z
DTEND:20221212T170000Z
URL:https://math.msu.edu/Seminars/TalkView.aspx?talk=29431
END:VEVENT
END:VCALENDAR