Talk_id  Date  Speaker  Title 
14372

Monday 8/20 11:00 AM

Soumyashant Nayak, University of Pennsylvania

Analyticity in Operator Algebras
 Soumyashant Nayak, University of Pennsylvania
 Analyticity in Operator Algebras
 08/20/2018
 11:00 AM  12:00 PM
 C517 Wells Hall
The title of this talk is borrowed from a seminal paper by Arveson discussing noncommutative analogues of the Hardy space H^∞(T) via the socalled subdiagonal algebras. Subdiagonal algebras are a family of nonselfadjoint operator algebras which give a common perspective to the study of some triangular operator algebras (for example, the algebra of block upper triangular matrices in M_n(C)), Dirichlet function algebras, etc. The first part of the talk will be about a noncommutative version of innerouter factorization in finite maximal subdiagonal algebras. We will then discuss a proof of a version of Jensen's inequality in this setting which relates to some classical results by Szegö.

14373

Friday 8/24 4:10 PM

Hyenkyun Woo, Korea University of Technology & Education

Bregmandivergence for Legendre exponential families and data analysis
 Hyenkyun Woo, Korea University of Technology & Education
 Bregmandivergence for Legendre exponential families and data analysis
 08/24/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
Bregmandivergence is a wellknown generalized distance framework in various applications, such as machine learning and image processing. In this talk, by using dual structure of the Bregmandivergence associated with the subclass of convex function of Legendre function, we analyze the structure of the Legendre exponential families whose cumulant function corresponds to the conjugate convex function of Legendre type. Actually, Legendre exponential families are the extended version of the regular exponential families to include nonregular exponential families, such as the inverse Gaussian distribution. The main advantage of the proposed Bregmandivergencebased approach is that it offers systematic successive approximation tools to handle closed domain issues arising in nonregular exponential families and the statistical distribution having discrete random variables, such as Bernoulli distribution and Poisson distribution. In addition, we also introduce the generalized centerbased clustering algorithm based on the Tweedie distribution.

14375

Friday 8/31 4:10 PM

Gerard Awanou, University of Illinois, Chicago

Discrete Aleksandrov solutions of the MongeAmpere equation
 Gerard Awanou, University of Illinois, Chicago
 Discrete Aleksandrov solutions of the MongeAmpere equation
 08/31/2018
 4:10 PM  5:00 PM
 1502 Engineering Building
A discrete analogue of the Dirichlet problem of the Aleksandrov theory of the MongeAmere equation is derived in this paper. The discrete solution is not required to be convex, but only discrete convex in the sense of Oberman. We prove that the uniform limit on compact subsets of discrete convex functions which are uniformly bounded and which interpolate the Dirichlet boundary data is a continuous convex function which satisfies the boundary condition strongly. The domain of the solution needs not be uniformly convex. We obtain the first proof of convergence of a wide stencil finite difference scheme to the Aleksandrov solution of the elliptic MongeAmpere equation when the right hand side is a sum of Dirac masses. The discrete scheme we analyze for the Dirichlet problem, when coupled with a discretization of the second boundary condition, as proposed by Benamou and Froese, can be used to get a good initial guess for geometric methods solving optimal transport between two measures.

13345

Thursday 9/6 2:00 PM

Alex Waldron, MSU

YangMills flow in dimension four
 Alex Waldron, MSU
 YangMills flow in dimension four
 09/06/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
Among the classical geometric evolution equations, YM flow is the least nonlinear and best behaved. Nevertheless, curvature concentration is a subtle problem when the base manifold has dimension four. I'll discuss my proof that finitetime singularities do not occur, and briefly describe the infinitetime picture.

15388

Thursday 9/6 3:00 PM

Daping Weng, MSU

Cluster DonaldsonThomas Transformation of Grassmannian
 Daping Weng, MSU
 Cluster DonaldsonThomas Transformation of Grassmannian
 09/06/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
Abstract: On the one hand, there is a 3d Calabi Yau category with stability conditions associated to a quiver without loops or 2cycles with generic potential, and one can study its DonaldsonThomas invariants. On the other hand, such a quiver also defines a cluster Poisson variety, which is constructed by gluing a collection of algebraic tori in a certain way governed by combinatorics. In certain cases, the DonaldsonThomas invariants of the former category can be captured by an automorphism on the latter space. In this talk, I will recall the cluster Poisson structure on the moduli space of configurations of points in a projective space, and state my result on constructing the corresponding cluster DonaldsonThomas transformation, and give a new proof of Zamolodchikov’s periodicity conjecture in the $A_m\boxtimes A_n$ cases as an application. If time permits, I will also talk about the generalization of this result to double Bruhat cells.

14378

Friday 9/7 4:10 PM

Tom Needham, Ohio State University

GromovMonge Quasimetrics and Distance Distributions
 Tom Needham, Ohio State University
 GromovMonge Quasimetrics and Distance Distributions
 09/07/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
In applications in computer graphics and computational anatomy, one seeks measurepreserving maps between shapes which preserve geometry as much as possible. Inspired by this, we define a distance between arbitrary compact metric measure spaces by blending the Monge formulation of optimal transport with the GromovHausdorff construction. We show that the resulting distance is an extended quasimetric on the space of compact mmspaces, which has convenient lower bounds defined in terms of distance distributions. We provide rigorous results on the effectiveness of these lower bounds when restricted to simple classes of mmspaces such as metric graphs or plane curves.This is joint work with Facundo Mémoli.

15399

Monday 9/10 1:00 PM

Nick Ovenhouse, MSU

Hochschild Cohomology
 Nick Ovenhouse, MSU
 Hochschild Cohomology
 09/10/2018
 1:00 PM  1:50 PM
 C517 Wells Hall
I will give the basic definitions of Hochschild cohomology, and discuss interpretations of the first few cohomology groups H^0, H^1, and H^2. Time permitting, I will discuss how the groups H^2 and H^3 are related to formal deformations of algebras and quantization of Poisson brackets.

15401

Wednesday 9/12 4:00 PM

Alex Waldron, MSU

YangMills flow in dimension four
 Alex Waldron, MSU
 YangMills flow in dimension four
 09/12/2018
 4:00 PM  4:50 PM
 C517 Wells Hall
Among the classical geometric evolution equations, YM flow is the least nonlinear and best behaved. Nevertheless, curvature concentration is a subtle problem when the base manifold has dimension four. I'll discuss my proof that finitetime singularities do not occur, and briefly describe the infinitetime picture.
This talk will be more analytic and contains <50% overlap with my talk last Thursday.

15400

Thursday 9/13 1:00 PM

Leonardo Abbrescia, MSU

Newton's method and periodic solutions of nonlinear wave equations
 Leonardo Abbrescia, MSU
 Newton's method and periodic solutions of nonlinear wave equations
 09/13/2018
 1:00 PM  2:00 PM
 C304 Wells Hall
We will introduce the paper of Walter Craig and C. E. Wayne of the same name as the title of the talk. We will hopefully cover the first eleven pages.

13292

Thursday 9/13 2:00 PM

Rita Gitik, Michigan

On Tame Subgroups of Finitely Presented Groups
 Rita Gitik, Michigan
 On Tame Subgroups of Finitely Presented Groups
 09/13/2018
 2:00 PM  2:50 PM
 C304 Wells Hall
We describe several examples of tame subgroups of finitely presented groups and prove that the fundamental groups of certain finite graphs of groups are locally tame.

15393

Thursday 9/13 3:00 PM

Dylan Rupel, MSU

The Combinatorics of Compatible Pairs
 Dylan Rupel, MSU
 The Combinatorics of Compatible Pairs
 09/13/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
Abstract: Compatible subsets of edges in a maximal Dyck path were introduced by Lee, Li, and Zelevinsky as a tool for constructing nice bases for rank two cluster algebras. In this talk, I will present a generalization of this combinatorics and give two applications. The first application is a combinatorial construction of noncommutative rank two generalized cluster variables which proves a conjecture of Kontsevich. The second application gives a combinatorial description of the cells in an affine paving of rank two quiver Grassmannians, this part is joint work with Thorsten Weist.

15384

Thursday 9/13 4:10 PM


Postdoc Lightning Talks

 Postdoc Lightning Talks
 09/13/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
No abstract available.

14376

Friday 9/14 4:10 PM

Dongwook Lee, University of California, Santa Cruz

New Polynomialfree, Variable Highorder Methods using Gaussian Process Modeling for CFD
 Dongwook Lee, University of California, Santa Cruz
 New Polynomialfree, Variable Highorder Methods using Gaussian Process Modeling for CFD
 09/14/2018
 4:10 PM  5:00 PM
 1502 Engineering Building
In this talk, an entirely new class of highorder numerical algorithms for computational fluid dynamics is introduced. The new method is based on the Gaussian Processes (GP) modeling that generalizes the Gaussian probability distribution. The new approach is to adopt the idea of the GP prediction technique which utilizes the covariance kernel functions and use it to interpolate and/or reconstruct highorder approximations for computational fluid dynamics simulations. The new GP highorder method is proposed as a new numerical highorder formulation in finite difference and finite volume frameworks, alternative to the conventional polynomialbased approaches.

15404

Monday 9/17 1:00 PM

Joshua Ruiter, MSU

Absolute Values and Ostrowski's Theorem
 Joshua Ruiter, MSU
 Absolute Values and Ostrowski's Theorem
 09/17/2018
 1:00 PM  1:50 PM
 C517 Wells Hall
The notion of an absolute value function can be generalized to arbitrary fields; one example is the padic absolute value on the rational. Ostrowski's theorem classifies all absolute values on the rationals. An absolute value induces a metric in a natural way, so we can "complete" a field with respect to a given absolute value. We'll also discuss the close relationship between absolute values and discrete valuation rings.

14371

Monday 9/17 4:10 PM

Selman Akbulut, MSU

Where do SeibergWitten equations come from?
 Selman Akbulut, MSU
 Where do SeibergWitten equations come from?
 09/17/2018
 4:10 PM  5:30 PM
 C304 Wells Hall
The question in title is akin to asking where the equation of motion of a free falling object a + bt + 1/2 gt^2 in 3space come from? then discovering that the "objects fall with constant acceleration" rule. Similarly, we derive SeibergWitten equations (which also have a linear part and a quadratic part) from the deformation equations of an "isotropic associative submanifold" of a complex G_2 Manifold. For this, we will define the notion of complex G_2 manifold and notion of complexification of a G_2 manifold (this is a joint work with Ustun Yildirim).

15402

Monday 9/17 4:10 PM

Andrew Krause; David Bramer

MTH 124  Inclusivity Enhancements
 Andrew Krause; David Bramer
 MTH 124  Inclusivity Enhancements
 09/17/2018
 4:10 PM  5:00 PM
 C109 Wells Hall
No abstract available.

15407

Wednesday 9/19 4:00 PM

Zhe Zhang (Alan)

Elliptic Regularity of JHolomorphic Curves
 Zhe Zhang (Alan)
 Elliptic Regularity of JHolomorphic Curves
 09/19/2018
 4:00 PM  4:50 PM
 A202 Wells Hall
One of the fundamental estimates for the L^p theory of elliptic operators is CalderonZygmund inequality. I’ll follow Mcduff & Salamon’s book for the proof of regularity theorem, raising the order of nonlinear Cauchy Riemann equation and making use of mean value property.

14348

Wednesday 9/19 4:10 PM

Richard Kollar, Comenius University, Bratislava, Slovakia

Krein signature  three unexpected lessons
 Richard Kollar, Comenius University, Bratislava, Slovakia
 Krein signature  three unexpected lessons
 09/19/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
Krein signature is an algebraic quantity characterizing purely imaginary eigenvalues of linearized Hamiltonian systems. Instabilities growing from a stable state in these systems are caused by HamiltonianHopf bifurcations, i.e. events when two purely imaginary eigenvalues collide and split off the imaginary axis. The necessary condition for such an event is that the colliding eigenvalues must have mixed signature. In the talk we present three elegant results related to Krein signature  graphical Krein signature and its use to simplify proofs, a connection to stability in general extended systems, and ability to characterize the nature of the eigenvalue collisions directly from the reduced dispersion relation.

15418

Thursday 9/20 3:00 PM

Matthew Mills, MSU

Green sequences and localacyclicity.
 Matthew Mills, MSU
 Green sequences and localacyclicity.
 09/20/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
In 2014 it was conjectured that the equality of the cluster algebra and upper cluster algebra is equivalent to the existence of a maximal green sequence. In this talk we will discuss a stronger result for cluster algebras from mutationfinite quivers with an emphasis on surface cluster algebras. Specifically we show that for all quivers from surface cluster algebras there exists a maximal green sequence if and only if the cluster algebra is equal to the cluster algebra if and only if the cluster algebra is locallyacyclic. We will also provide a counterexample to show that the result does not hold in general.

15378

Thursday 9/20 4:10 PM

Brendon Rhoades, University of California, San Diego

The combinatorics, algebra, and geometry of ordered set partitions
 Brendon Rhoades, University of California, San Diego
 The combinatorics, algebra, and geometry of ordered set partitions
 09/20/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
An {\em ordered set partition} of size $n$ is a set partition of $\{1, 2, \dots, n \}$ with a specified order on its blocks. When the number of blocks equals the number of letters $n$, an ordered set partition is just a permutation in the symmetric group $S_n$. We will discuss some combinatorial, algebraic, and geometric aspects of permutations (due to MacMahon, Carlitz, Chevalley, Steinberg, Artin, LusztigStanley, Ehresmann, Borel, and LascouxSch\"utzenberger). We will then describe how these results generalize to ordered set partitions and discuss a connection with the HaglundRemmelWilson {\em Delta Conjecture} in the field of Macdonald polynomials. Joint with Jim Haglund, Brendan Pawlowski, and Mark Shimozono.

15421

Friday 9/21 4:10 PM

Jeff Schenker

NSF Fellowship Info Session
 Jeff Schenker
 NSF Fellowship Info Session
 09/21/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
No abstract available.

15422

Monday 9/24 1:00 PM


NSA Info Session

 NSA Info Session
 09/24/2018
 1:00 PM  2:00 PM
 C304 Wells Hall
The SPORT program at the National Security Agency (NSA) offers graduate students the opportunity to apply their academic knowledge in a stimulating professional environment. As a SPORT intern you will work closely with full time Operations Research analysts applying academic and technical skills to challenging, realworld problems. Internships are paid and are 12 weeks in duration (MayAugust). Applications accepted September 1st through October 31st

15425

Monday 9/24 1:00 PM

Chuangtian Guan, MSU

Witt Schemes and Witt Vectors
 Chuangtian Guan, MSU
 Witt Schemes and Witt Vectors
 09/24/2018
 1:00 PM  1:50 PM
 C517 Wells Hall
No abstract available.

15408

Wednesday 9/26 4:00 PM

Nick Ovenhouse

Noncommutative Geometry and Character Varieties
 Nick Ovenhouse
 Noncommutative Geometry and Character Varieties
 09/26/2018
 4:00 PM  5:00 PM
 A202 Wells Hall
Roughly speaking, noncommutative geometry studies noncommutative rings and algebras from a "geometric" perspective. I will discuss some philosophies and approaches to the subject, which leads to the study of character varieties, which I will define and discuss.

15428

Thursday 9/27 1:00 PM

Wenchuan Tian, MSU

Newton's method and periodic solutions of nonlinear wave equations
 Wenchuan Tian, MSU
 Newton's method and periodic solutions of nonlinear wave equations
 09/27/2018
 1:00 PM  2:00 PM
 C304 Wells Hall
We will cover pages 12  23 of the paper by Walter Craig and C.E. Wayne of the same title. These pages cover section 2.4 until the end of the proof of Lemma 3.3.

15396

Thursday 9/27 2:00 PM

Giuseppe Martone, University of Michigan

Hitchin representations and positive configurations of apartments
 Giuseppe Martone, University of Michigan
 Hitchin representations and positive configurations of apartments
 09/27/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
Hitchin singled out a preferred component in the character variety of representations from the fundamental group of a surface to PSL(d,R). When d=2, this Hitchin component coincides with the Teichm\"uller space consisting of all hyperbolic metrics on the surface. Later Labourie showed that Hitchin representations share many important differential geometric and dynamical properties.
Parreau extended previous work of Thurston and MorganShalen to a compactification of the Hitchin component whose boundary points are described by actions of the fundamental group of the surface on a building.
In this talk, we offer a new point of view for the Parreau compactification, which is based on certain positivity properties discovered by Fock and Goncharov. Specifically, we use the FockGoncharov construction to describe the intersection patterns of apartments in invariant subsets of the building that arises in the boundary of the Hitchin component.

15398

Thursday 9/27 3:00 PM


Joint meeting with Notre Dame: open problem session

 Joint meeting with Notre Dame: open problem session
 09/27/2018
 3:00 PM  4:00 PM
 C304 Wells Hall
Abstract: we will discuss open problems in Cluster Algebras theory

15381

Thursday 9/27 4:10 PM

Igor Dolgachev, University of Michigan

The reflection group of a regular tetrahedron
 Igor Dolgachev, University of Michigan
 The reflection group of a regular tetrahedron
 09/27/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
I will explain how the group of affine orthogonal transformations generated by the reflections into the four facets of a regular tetrahedron and its symmetries appears as a discrete group of motions of the 9dimensional hyperbolic space, as the full group of automorphisms of some algebraic surfaces and as a lattice in a projective linear group over the 3adic numbers.

15424

Monday 10/1 4:10 PM

Kursat Sozer, IU

Extended HQFTs in dimension 2
 Kursat Sozer, IU
 Extended HQFTs in dimension 2
 10/01/2018
 4:10 PM  5:30 PM
 C304 Wells Hall
Topological quantum field theories (TQFTs), inspired by theoretical physics, produce manifold invariants behaving well under gluing. For every discrete group G, homotopy quantum field theories (HQFTs) are Gequivariant versions of TQFTs. In this talk we define and classify 2dimensional extended HQFTs by generalizing methods introduced for TQFTs by Chris SchommerPries in 2009. We list generators and relations for the extended Gequivariant bordism bicategory and use them to classify 2dimensional extended HQFTs.

15427

Wednesday 10/3 12:00 PM

Dr. Kaitlin Torphy, MSU

Educational Professionalism within the Fifth Estate: Networks of Influence Within Social Media and Education
 Dr. Kaitlin Torphy, MSU
 Educational Professionalism within the Fifth Estate: Networks of Influence Within Social Media and Education
 10/03/2018
 12:00 PM  1:00 PM
 B310 Wells Hall
Dr. Kaitlin Torphy will speak about an emergent phenomenon, social media in education. She will present the notion of a Fifth Estate within the digital age, redefining network influence (Dutton, 2009). Dr. Torphy will review research regarding teachers’ engagement within Pinterest, a prevalent social media platform amongst teachers nationwide. In related work, she will explore how teachers are turning to social media (Pinterest) to connect with instructional resources and one another as they work to support the academic needs of their students and respond to education reforms. Dr. Torphy will provide a first look at characterizing the quality and standards alignment of over 5000 mathematics tasks within Pinterest. For more information on the work or the Teachers in Social Media project, visit www.TeachersInSocialMedia.org.

15437

Wednesday 10/3 2:00 PM

Alex Waldron, MSU

Introduction to the harmonic map problem
 Alex Waldron, MSU
 Introduction to the harmonic map problem
 10/03/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
First in a series of talks covering existence and regularity results for harmonic maps between manifolds. (Reference: Lin and Wang's book.)

15426

Wednesday 10/3 4:10 PM

Keshav Sutrave

Take a walk on a Riemann surface
 Keshav Sutrave
 Take a walk on a Riemann surface
 10/03/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
This talk will be an introduction to Riemann surfaces, including branched covering and monodromy in this setting. I will prove Riemann's existence theorem of branched covers, illustrate this using algebraic curves, and finish with RiemannHurwitz.

15389

Wednesday 10/3 4:10 PM

N. K. Nikolski, University of Bordeaux

V.Ya.Kozlov's completeness problem
 N. K. Nikolski, University of Bordeaux
 V.Ya.Kozlov's completeness problem
 10/03/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
In 19481950, V.Ya.Kozlov (19142007) stated a series of
interesting geometric properties of dilated systems D(f)= {f(kx): k=
1,2,...} in the spaces L^p(0,1). Since that, no proofs were published.
In particular, for a RademacherHaarWalsh type generator f=
2periodic odd extension of the indicator function of (0,a), 0<a<1,
the system D(f) was claimed to be complete/incomplete for many
particular values of a. We prove all Kozlov's statements and several
new, as well as discuss other geometric properties of D(f).

15419

Thursday 10/4 11:00 AM

Ramis Movassagh, IBM

Unitary paths and quantum computational supremacy: A proof of averagecase hardness of Random Circuit Sampling
 Ramis Movassagh, IBM
 Unitary paths and quantum computational supremacy: A proof of averagecase hardness of Random Circuit Sampling
 10/04/2018
 11:00 AM  12:00 PM
 C304 Wells Hall
Demonstration of computational advantages of Noisy IntermediateScale Quantum (NISQ) computers over classical computers is an imperative nearterm goal, especially with the exuberant experimental frontier in academia and industry. Because of a large industrial push (e.g., from IBM and Google), NISQ computers with hundred(s) of qubits are at the brink of existence with the promise of outperforming any classical computer.
A goalpost is to demonstrate the so called {\it quantum computational supremacy}, which is to show that a NISQ computer can perform a computational task that is tremendously difficult for any classical (super)computer. The foremost candidate problem to show quantum supremacy is Random Circuit Sampling (RCS), which is the task of sampling from the output distribution of a random circuit. For example, this is Google's primary current objective, whose delivery is promised within the next few months.
In this work, we first develop a mathematical framework for and prove various useful facts applicable to random circuits such as construction of rational function valued unitary paths that interpolate between two arbitrary unitaries, an extension of BerlekampWelch algorithm that efficiently and exactly interpolates rational functions, and construction of probability distributions over unitaries that are arbitrarily close to the Haar measure. Lastly, we then prove that the exact sampling from the output distribution of random circuits is $\#P$Hard on {\it average}; we also prove that this is necessary for proving the quantum supremacy conjecture.

14370

Thursday 10/4 2:00 PM

Artem Kotelskiy, Indiana University

Khovanov homology and BarNatan's deformation via immersed curves in the 4punctured sphere.
 Artem Kotelskiy, Indiana University
 Khovanov homology and BarNatan's deformation via immersed curves in the 4punctured sphere.
 10/04/2018
 2:00 PM  2:50 PM
 C304 Wells Hall
We will describe a geometric interpretation of Khovanov homology and its deformation due to BarNatan as Lagrangian Floer homology of two immersed curves in the 4punctured 2sphere S^2 \ 4pt. We will first start with a certain cobordism theoretic algebra H, where elements are all cobordisms between two trivial tangles )( and = up to certain relations. The central point then will be the observation that this algebra is isomorphic to an algebra B = Fuk(a0, a1), whose elements are generators of wrapped Lagrangian Floer complexes between two arcs a0 and a1 inside S^2 \ 4pt. The results will follow because D structures over H give Khovanov/BarNatan invariants for 4ended tangles, and D structures over B give curves in S^2 \ 4pt (due to [Haiden, Katzarkov, Kontsevich]).
The construction is originally inspired by a result of [Hedden, Herald, Hogancamp, Kirk], which embeds 4ended reduced Khovanov arc algebra (or, equivalently, BarNatan dotted cobordism algebra) into the Fukaya category of the 4punctured sphere. This is joint work with Liam Watson and Claudius Zibrowius.

15430

Thursday 10/4 3:00 PM

Dylan Rupel, MSU

Cell Decompositions for Rank Two Quiver Grassmannians
 Dylan Rupel, MSU
 Cell Decompositions for Rank Two Quiver Grassmannians
 10/04/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
A quiver Grassmannian is a variety parametrizing subrepresentations of a given quiver representation. Reineke has shown that all projective varieties can be realized as quiver Grassmannians. In this talk, I will study a class of smooth projective varieties arising as quiver Grassmannians for (truncated) preprojective representations of an nKronecker quiver, i.e. a quiver with two vertices and n parallel arrows between them. The main result I will present is a recursive construction of cell decompositions for these quiver Grassmannians. If there is time I will discuss a combinatorial labeling of the cells by which their dimensions may conjecturally be directly computed. This is a report on joint work with Thorsten Weist.

15420

Thursday 10/4 4:10 PM

Yang Yang, Michigan State University

Some inverse source and coefficient problems for the wave operators (special colloquium)
 Yang Yang, Michigan State University
 Some inverse source and coefficient problems for the wave operators (special colloquium)
 10/04/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
Inverse problems seek to infer causal factor from the resulting observation, and waves are among the most prevalent and significant observations in nature. In this talk, we will discuss two inverse problems for the acoustic wave equation and its generalizations. The first is an inverse source problem where one attempts to determine an instantaneous source from the boundary Dirichlet data. We give sharp conditions on unique and stable determination, and derive an explicit reconstruction formula for the source. The second is an inverse coefficient problem on a cylinderlike Lorentzian manifold (M,g) for the Lorentzian wave operator perturbed by a vector field A and a function q. We show that local knowledge of the DirichlettoNeumann map (DNmap) stably determines the jets of (g,A,q) up to gauge transformations, and global knowledge of the DNmap stably determines the lens relation of g as well as the light ray transforms of A and q. This is based on joint work with P. Stefanov.

15432

Friday 10/5 4:10 PM

Igor Rapinchuk

On the infinitude of primes
 Igor Rapinchuk
 On the infinitude of primes
 10/05/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
Prime numbers are the building blocks of arithmetic. Starting with Euclid's classical proof that there are infinitely many primes, I will discuss various approaches to thinking about the infinitude of primes, culminating with Dirichlet's theorem on primes in arithmetic progression.

15441

Monday 10/8 1:00 PM

Charlotte Ure, MSU

Étale Cohomology and its Applications to Curves
 Charlotte Ure, MSU
 Étale Cohomology and its Applications to Curves
 10/08/2018
 1:00 PM  1:50 PM
 C517 Wells Hall
Étale cohomology was originally introduced by Grothendieck in the 1960s as a tool for solving the Weil conjectures. Since then it has proven very useful in algebraic and arithmetic geometry. In my talk, I will introduce the notion of Grothendieck topology, étale site, and étale cohomology. I will then explore the cohomology of curves and briefly describe some applications. This talk will be accessible to all levels.

15433

Monday 10/8 4:10 PM

Rachael Lund and Tsveta Sendova

MTH 101 updates and ULA coordination
 Rachael Lund and Tsveta Sendova
 MTH 101 updates and ULA coordination
 10/08/2018
 4:10 PM  5:00 PM
 C109 Wells Hall
We are going to discuss changes to the MTH 101 curriculum, ideas about some changes to the structure going forward.

15405

Monday 10/8 4:10 PM

Selman Akbulut, MSU

A simple family of infinitely many absolutely exotic manifolds
 Selman Akbulut, MSU
 A simple family of infinitely many absolutely exotic manifolds
 10/08/2018
 4:10 PM  5:30 PM
 C304 Wells Hall
I wıll demonstrate a smooth 4manifold M, obtained by attaching a 2handle to B^4 along a certain knot K in S^3, which admits infinitely many absolutely exotic copies M_n, n=0,1,2.., such that each copy M_n is obtained by attaching 2handle to a fixed compact smooth contractible manifold W along its boundary Y, along the iterates f^{n}(c) of a knot c in Y by a diffeomorphism f: Y> Y. This generalizes the example I gave in “An exotic 4manifold, Jour. of Diff. Geom. 33, (1991)” which corresponds to the n=1 case.

15439

Wednesday 10/10 2:00 PM

Gorapada Bera

Morrey's theorem
 Gorapada Bera
 Morrey's theorem
 10/10/2018
 2:00 PM  3:15 PM
 C304 Wells Hall
Regularity of minimizing harmonic maps in dimension 2.

15409

Wednesday 10/10 4:10 PM

Sanjay Kumar

TuraevViro invariants via quantum representations of the mapping class group
 Sanjay Kumar
 TuraevViro invariants via quantum representations of the mapping class group
 10/10/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
The TuraevViro invariants are an infinite family of real valued 3manifold invariants originally defined by state sums of a triangulation. Using SO(3)TQFT, I will demonstrate an equivalent formulation in terms of traces of quantum representations and discuss its possible advantages in studying mapping tori of surfaces.

15390

Wednesday 10/10 4:10 PM

N. K. Nikolski, University of Bordeaux

Dilated systems and multivariable analysis
 N. K. Nikolski, University of Bordeaux
 Dilated systems and multivariable analysis
 10/10/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
Geometric L^2(0,1) properties of dilated function systems D(f)= {f(kx): k= 1,2,...} are discussed, as completeness, Riesz basis property, etc. (Completeness of D(f) for f(x)= 1/x[1/x] is equivalent to the Riemann Hypothesis). The Bohr's lift techniques permit to explain (all) known results and show some new, as well as to discuss open problems.

15436

Thursday 10/11 11:00 AM

Vitali Vougalter, U Toronto

Existence in the sense of sequences of stationary solutions for some nonFredholm integrodifferential equations
 Vitali Vougalter, U Toronto
 Existence in the sense of sequences of stationary solutions for some nonFredholm integrodifferential equations
 10/11/2018
 11:00 AM  12:00 PM
 C304 Wells Hall
We establish the existence in the sense of sequences of
stationary solutions for some reactiondiffusion type equations in
appropriate
H^2 spaces. It is shown that, under reasonable technical conditions, the
convergence in L^1 of the integral kernels implies the existence and
convergence in H^2 of solutions. The nonlocal elliptic equations involve
second order differential operators with and without the Fredholm property.

15379

Thursday 10/11 2:00 PM

Matthew Stoffregen, MIT

An infiniterank summand of the homology cobordism group
 Matthew Stoffregen, MIT
 An infiniterank summand of the homology cobordism group
 10/11/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
This talk explains a generalization of the techniques that Hom introduced to construct an infiniterank summand of the topologically slice knot concordance group. We generalize Hom's epsiloninvariant to the involutive Heegaard Floer homology constructed by HendricksManolescu. As an application, we see that there is an infiniterank summand of the homology cobordism group, generated by Seifert spaces. The talk will contain a review of involutive Floer homology. This is joint work with Irving Dai, Jen Hom, and Linh Truong.

15440

Thursday 10/11 3:00 PM

SungSoo Byun, Seoul National University

Annulus SLE partition functions and martingaleobservables
 SungSoo Byun, Seoul National University
 Annulus SLE partition functions and martingaleobservables
 10/11/2018
 3:00 PM  3:50 PM
 C405 Wells Hall
In this talk, I will introduce a version of conformal ﬁeld theory (CFT) and explain its implementations to SLE theory in a doubly connected domain. The basic fields in these implementations are oneparameter family of Gaussian free fields whose boundary conditions are given by a weighted combination of Dirichlet boundary condition and excursionreflected one. After explaining basic notions in CFT such as OPE families of central charge modiﬁcations of the Gaussian free ﬁeld and presenting certain equations including a version of EguchiOoguri and Ward’s equations, I will outline the relation between CFT and SLE theory. As an application, I will explain how to apply the method of screening to find Euler integral type solutions to the parabolic partial differential equations for the annulus SLE partition functions introduced by Zhan and present a class of SLE martingaleobservables associated with these solutions.
This is based on joint work with NamGyu Kang and HeeJoon Tak.

15431

Thursday 10/11 3:00 PM

Nick Ovenhouse, MSU

Introduction to Scattering Diagrams
 Nick Ovenhouse, MSU
 Introduction to Scattering Diagrams
 10/11/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
I will give basic definitions of scattering diagrams and wallcrossing automorphims, and finish by showing some examples related to rank2 cluster algebras.

14349

Thursday 10/11 4:10 PM

Deanna Needell, University of California, Los Angeles

Simple Classification from Binary Data
 Deanna Needell, University of California, Los Angeles
 Simple Classification from Binary Data
 10/11/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
Binary, or onebit, representations of data arise naturally in many applications, and are appealing in both hardware implementations and algorithm design. In this talk, we provide a brief background to sparsity and 1bit measurements, and then present new results on the problem of data classification from binary data that proposes a framework with low computation and resource costs. We illustrate the utility of the proposed approach through stylized and realistic numerical experiments, provide a theoretical analysis for a simple case, and discuss future directions.

15447

Monday 10/15 4:10 PM

Michael Brown, MSU

Math Courses for Education Majors: Philosophies and Experiences
 Michael Brown, MSU
 Math Courses for Education Majors: Philosophies and Experiences
 10/15/2018
 4:10 PM  5:00 PM
 C109 Wells Hall
No abstract available.

16444

Wednesday 10/17 2:00 PM

Woong Bae Park, MSU

Regularity of minimizing harmonic maps in general dimensions
 Woong Bae Park, MSU
 Regularity of minimizing harmonic maps in general dimensions
 10/17/2018
 2:00 PM  3:30 PM
 C304 Wells Hall
First talk on SchoenUhlenbeck partial regularity theorem for minimizing harmonic maps.

15410

Wednesday 10/17 4:10 PM

Michael Shultz

The homology polynomial and pseudoAnosov braids
 Michael Shultz
 The homology polynomial and pseudoAnosov braids
 10/17/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
Every orientation preserving homeomorphism of a compact, connected, orientable surface S is isotopic to a representative that is periodic, reducible, or pseudoAnosov (pA). In the last case, the representative is neither periodic nor reducible and the surface admits two (singular) transverse measured foliations. The pA representative "stretches" with respect to one of these measures by a number called the stretch factor.
The homology polynomial, introduced by Birman, Brinkmann, and Kawamuro, is an invariant of the isotopy class and contains the stretch factor as it's largest real root. It can also distinguish some distinct pA maps with the same stretch factor. In this talk I will discuss the ideas behind the homology polynomial and how it is obtained. As time permits I will discuss some examples involving pA braids and touch on a connection with the Burau representation.

15434

Thursday 10/18 2:00 PM

Siddhi Krishna, Boston College

Taut Foliations, Positive 3Braids, and the LSpace Conjecture
 Siddhi Krishna, Boston College
 Taut Foliations, Positive 3Braids, and the LSpace Conjecture
 10/18/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
The LSpace Conjecture is taking the lowdimensional topology community by storm. It aims to relate seemingly distinct Floer homological, algebraic, and geometric properties of a closed 3manifold Y. In particular, it predicts a 3manifold Y isn't "simple" from the perspective of HeegaardFloer homology if and only if Y admits a taut foliation. The reverse implication was proved by Ozsvath and Szabo. In this talk, we'll present a new theorem supporting the forward implication. Namely, we'll use branched surfaces to build taut foliations for manifolds obtained by surgery on positive 3braid closures. As an example, we'll construct taut foliations in every nonLspace obtained by surgery along the P(2,3,7) pretzel knot. No background in HeegaardFloer or foliation theories will be assumed.

15435

Thursday 10/18 2:30 PM

Dr. Kyeong Hah Roh, Arizona State University

On the Teaching and Learning of Logic in Mathematical Contents
 Dr. Kyeong Hah Roh, Arizona State University
 On the Teaching and Learning of Logic in Mathematical Contents
 10/18/2018
 2:30 PM  4:00 PM
 252 EH
Logical thinking plays a crucial role in generating valid arguments from the given information as well as in evaluating the validity of others’ arguments in workplaces. Training our students as logical thinkers has been a central component in mathematics education. By engaging in proving and validating activities in undergraduate mathematics, students are expected to enhance logical thinking and make sound decisions by deducing valid inferences from a tremendous amount of information and resources in their future workplaces. Many universities in the United States thus offer introductory proof courses, or so called transitiontoproof courses, to introduce logic and various proof structures for valid arguments in mathematical contents. This presentation will provide an overview of the empirical studies that I have been involved in relation to undergraduate students’ logic and logical thinking, instructional interventions that I have designed to enhance students’ logical thinking in mathematical contents, and some issues and challenges in the introductory proof courses in mathematics.

16446

Thursday 10/18 3:00 PM

Erkan Nane, Auburn University

Blowup Results for Spacetime Fractional Dynamics
 Erkan Nane, Auburn University
 Blowup Results for Spacetime Fractional Dynamics
 10/18/2018
 3:00 PM  3:50 PM
 C405 Wells Hall
Linked Abstract
ABSTRACT. Consider nonlinear timefractional stochastic reactiondiffusion equations of the following type,
$$
\partial^\beta_tu_t(x)=\nu(\Delta)^{\alpha/2} u_t(x)+I^{1\beta}_t[b(u)+ \sigma(u)\stackrel{\cdot}{F}(t,x)]
$$
in $(d+1)$ dimensions, where $\nu>0, \beta\in (0,1)$, $\alpha\in (0,2]$. The operator $\partial^\beta_t$ is the Caputo fractional derivative while $(\Delta)^{\alpha/2} $ is the generator of an isotropic $\alpha$stable L\'evy process and $I^{1\beta}_t$ is the Riesz fractional integral operator. The forcing noise denoted by $\stackrel{\cdot}{F}(t,x)$ is a Gaussian noise. These equations might be used as a model for materials with random thermal memory. We derive nonexistence (blowup) of global random field solutions under some additional conditions, most notably on $b$, $\sigma$ and the initial condition. Our results complement those of P. Chow in ``P.L. Chow. Unbounded positive solutions of nonlinear parabolic It$\hat{o}$ equations. Commun. Stoch. Anal., 3(2)(2009), 211222.'' and ``P.L. Chow. Explosive solutions of stochastic reactiondiffusion equations in mean $l_{p}$norm. J. Differential Equations, 250(5) (2011), 25672580.'' and Foondun and Parshad ``M. Foondun and R. Parshad, On nonexistence of global solutions to a class of stochastic heat equations. Proc. Amer. Math. Soc. 143 (2015), no. 9, 40854094'', among others. The results presented are our recent joint work with Sunday Asogwa, Mohammud Foondun, Wei Liu, and Jebessa Mijena.

16443

Thursday 10/18 3:00 PM

Dylan Rupel, MSU

Cluster Monomials and Theta Bases via Scattering Diagrams
 Dylan Rupel, MSU
 Cluster Monomials and Theta Bases via Scattering Diagrams
 10/18/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
In this talk I will add to Nick’s presentation from last time by describing a portion of the scattering diagram using cvectors and gvectors. Then I will present some examples of computing cluster monomials using broken lines. If there is time I will compute an element of the theta basis which is not a cluster monomial.

16445

Thursday 10/18 3:10 PM

Min Hoon Kim, KIAS

A family of freely slice good boundary links
 Min Hoon Kim, KIAS
 A family of freely slice good boundary links
 10/18/2018
 3:10 PM  4:00 PM
 C304 Wells Hall
The still open topological surgery conjecture for 4manifolds is equivalent to the statement that all good boundary links are freely slice. In this talk, I will show that every good boundary link with a pair of derivative links on a Seifert surface satisfying a homotopically trivial plus assumption is freely slice. This subsumes all previously known methods for freely slicing good boundary links with two or more components, and provides new freely slice links. This is joint work with Jae Choon Cha and Mark Powell.

14361

Thursday 10/18 4:10 PM

Frank Morgan, Williams College

Double Soap Bubbles and Densities
 Frank Morgan, Williams College
 Double Soap Bubbles and Densities
 10/18/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
The familiar double soap bubble is the leastarea way to enclose and separate two given volumes in Euclidean space. What if you give space a density, such as r^2 or e^r^2 or e^r^2? The talk will include recent results and open questions. Students welcome.

15445

Friday 10/19 4:10 PM

Paul Bendich, Duke University and Geometric Data Analytics

Topology and Geometry for Tracking and Sensor Fusion
 Paul Bendich, Duke University and Geometric Data Analytics
 Topology and Geometry for Tracking and Sensor Fusion
 10/19/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
Many systems employ sensors to interpret the environment. The targettracking task is to gather sensor data from the environment and then to partition these data into tracks that are produced by the same target. The goal of sensor fusion is to gather data from a heterogeneous collection of sensors (e.g, audio and video) and fuse them together in a way that enriches the performance of the sensor network at some task of interest.
This talk summarizes two recent efforts that incorporate mildly sophisticated mathematics into the general sensor arena.
First, a key problem in tracking is to 'connect the dots:' more precisely, to take a piece of sensor data at a given time and associate it with a previouslyexisting track (or to declare that this is a new object). We use topological data analysis (TDA) to form dataassociation likelihood scores, and integrate these scores into a wellrespected algorithm called Multiple Hypothesis Tracking. Tests on simulated data show that the TDA adds significant value over baseline, especially in the context of noisy sensor data.
Second, we propose a very general and entirely unsupervised sensor fusion pipeline that uses recent techniques from diffusion geometry and wavelet theory to fuse time series of arbitrary dimension arising from disparate sensor modalities. The goal of the pipeline is to differentiate classes of timeordered behavior sequences, and we demonstrate its performance on a wellstudied digit sequence database.
This talk represents joint work with many people. including Chris Tralie, Nathan Borggren, Sang Chin, Jesse Clarke, Jonathan deSena, John Harer, Jay Hineman, Elizabeth Munch, Andrew Newman, Alex Pieloch, David Porter, David Rouse, Nate Strawn, Adam Watkins, Michael Williams, and Peter Zulch.

16442

Friday 10/19 4:10 PM

Frank Morgan, Williams College

Distinguished Undergraduate Lecture: Optimal Tiles
 Frank Morgan, Williams College
 Distinguished Undergraduate Lecture: Optimal Tiles
 10/19/2018
 4:10 PM  5:00 PM
 B122 Wells Hall
A regular hexagon is the leastperimeter unitarea tile of the Euclidean plane. What is the best pentagonal tile? What about the hyperbolic plane? What about higher dimensions? The talk will include open questions and recent results, some by undergraduates.

15444

Tuesday 10/23 4:00 PM

Ekaterina Rapinchuk

Auction Dynamics for SemiSupervised Data Classification
 Ekaterina Rapinchuk
 Auction Dynamics for SemiSupervised Data Classification
 10/23/2018
 4:00 PM  5:00 PM
 C304 Wells Hall
We reinterpret the semisupervised data classification problem using an auction dynamics framework (inspired by real life auctions) in which elements of the data set make bids to the class of their choice. This leads to a novel forward and reverse auction method for data classification that readily incorporates classsize constraints into an accurate and efficient algorithm requiring remarkably little training/labeled data. We prove that the algorithm is unconditionally stable.

16450

Tuesday 10/23 4:10 PM

Huyi Hu , Michigan State University

Unstable entropy and pressure for partially hyperbolic systems
 Huyi Hu , Michigan State University
 Unstable entropy and pressure for partially hyperbolic systems
 10/23/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
We study ergodic properties caused by the unstable part of partially hyperbolic systems. We define unstable metric entropy, topological entropy and pressures, and prove the corresponding variational principles. For unstable metric entropy we obtain affineness, upper semicontinuity and a version of ShannonMcMillanBreiman theorem. We also obtain existence of Gibbs ustates, differentiability properties of unstable pressure, such as tangent functionals, Gateaux differentiability and Frechet differentiability.

16448

Wednesday 10/24 2:00 PM

Alex Waldron

Epsilonregularity of harmonic maps
 Alex Waldron
 Epsilonregularity of harmonic maps
 10/24/2018
 2:00 PM  3:30 PM
 C304 Wells Hall
Proof of the key partial regularity theorem for minimizing (and stationary) harmonic maps, and bound on Hausdorff measure of the singular set.

15411

Wednesday 10/24 4:10 PM

Woongbae Park

Bubbling of harmonic maps
 Woongbae Park
 Bubbling of harmonic maps
 10/24/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
Harmonic map is a generalization of harmonic function but has different behavior. I briefly introduce harmonic map and explain one of the differences, called bubbling. This is special kind of singularity only occurs under certain conditions. I explain how we deal with bubbling in different favors, and prove some details.

15406

Wednesday 10/24 4:10 PM

Maxim Gilula, MSU

l^2 decoupling with vanishing curvature
 Maxim Gilula, MSU
 l^2 decoupling with vanishing curvature
 10/24/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
I will discuss recent progress on decoupling for curves with vanishing curvature.

15386

Thursday 10/25 2:00 PM

William Worden, Rice University

Generic veering triangulations are not geometric
 William Worden, Rice University
 Generic veering triangulations are not geometric
 10/25/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
Abstract: Every pseudoAnosov mapping class \phi deﬁnes an associated veering triangulation \tau_\phi of a punctured mapping torus. We show that generically, \tau_\phi is not geometric. Here, the word “generic” can be taken either with respect to random walks in mapping class groups or with respect to counting geodesics in moduli space. After describing how veering triangulations are obtained from pseudoAnosov maps, we will discuss some tools that go into the proof and give an outline if time permits.

15442

Thursday 10/25 3:00 PM


MSUND Summit @ ND

 MSUND Summit @ ND
 10/25/2018
 3:00 PM  5:00 PM

We will be heading to Notre Dame to discuss open problems in the field. We will meet in room Hurley 258.

16449

Friday 10/26 4:10 PM

Akil Narayan, University of Utah

Sampling techniques for building computational emulators and highdimensional approximation
 Akil Narayan, University of Utah
 Sampling techniques for building computational emulators and highdimensional approximation
 10/26/2018
 4:10 PM  5:00 PM
 1502 Engineering Building
We present an overview of techniques for building mathematical emulators of parametrized scientific models. We will primarily discuss forward emulation, where one seeks to predict the output of a model given a parametric input. We will emphasize methods that boast stability, accuracy, and computational efficiency. The focus will be on emulators built from nonadapted polynomials, and time permitting we will also explore adapted approximations and reduced order modeling. The talk will highlight some recent notable advances made in the field of building emulators from sample data, and will identify frontiers where mathematical or computational advances are needed.

16447

Wednesday 10/31 2:00 PM

Woong Bae Park

Compactness properties of harmonic maps
 Woong Bae Park
 Compactness properties of harmonic maps
 10/31/2018
 2:00 PM  4:00 PM
 C304 Wells Hall
No abstract available.

16458

Wednesday 10/31 4:10 PM

Kristina Skreb

TBA
 Kristina Skreb
 TBA
 10/31/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
No abstract available.

15412

Wednesday 10/31 4:10 PM

Wenchuan Tian

A Compactness Theorem for Rotationally Symmetric Riemannian Manifolds with Positive Scalar Curvature
 Wenchuan Tian
 A Compactness Theorem for Rotationally Symmetric Riemannian Manifolds with Positive Scalar Curvature
 10/31/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
Gromov conjectured that sequences of compact Riemannian manifolds with
positive scalar curvature should have subsequences which converge in the
intrinsic flat sense to limit spaces with some generalized notion of scalar curvature.
In light of three dimensional examples discovered jointly with Basilio and Dodziuk,
Sormani suggested that one add an hypothesis assuming a uniform lower bound
on the area of a closed minimal surface. We have proven this revised conjecture
in the setting where the sequence of manifolds are 3 dimensional rotationally symmetric warped
product manifolds. This is a project given by professor Christina Sormani, and is joint work with Jiewon Park and Changliang Wang.

16453

Thursday 11/1 10:00 AM

Andrew Krause, MSU

TBA (special colloquium)
 Andrew Krause, MSU
 TBA (special colloquium)
 11/01/2018
 10:00 AM  11:00 AM
 C304 Wells Hall
TBA

15387

Thursday 11/1 11:00 AM

Yuanqi Wang

Moduli space of G2instantons on 7dimensional product manifolds
 Yuanqi Wang
 Moduli space of G2instantons on 7dimensional product manifolds
 11/01/2018
 11:00 AM  12:00 PM
 C304 Wells Hall
$G_2$instantons are 7dimensional analogues of flat
connections in dimension 3. It is part of DonaldsonThomas’ program to
generalize the fruitful gauge theory in dimensions 2,3,4 to dimensions 6,7,8.
The moduli space of $G_2$instantons, with virtual dimension 0, is
expected to have interesting geometric structure and yield enumerative
invariant for the underlying 7dimensional manifold.
In this talk, in some reasonable special cases and a fairly complete manner,
we will describe the relation between the moduli space of $G_2$instantons
and an algebraic geometry moduli on a CalabiYau 3fold.

16455

Thursday 11/1 2:30 PM

Keith Promislow, Chair, MSU

Special Presentation By Chair
 Keith Promislow, Chair, MSU
 Special Presentation By Chair
 11/01/2018
 2:30 PM  3:30 PM
 B122 Wells Hall
Five years as Chair

16462

Thursday 11/1 3:00 PM

Dylan Rupel, MSU

Cluster Monomials and Theta Bases via Scattering Diagrams
 Dylan Rupel, MSU
 Cluster Monomials and Theta Bases via Scattering Diagrams
 11/01/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
In this talk I will add to Nick’s presentation from last time by describing a portion of the scattering diagram using cvectors and gvectors. Then I will present some examples of computing cluster monomials using broken lines. If there is time I will compute an element of the theta basis which is not a cluster monomial.

15382

Thursday 11/1 4:10 PM

Rustum Choksi, McGill University

Nonlocal Geometric Variational Problems: Isotropic and Anisotropic Extensions of Gamow's Liquid Drop Problem and Beyond
 Rustum Choksi, McGill University
 Nonlocal Geometric Variational Problems: Isotropic and Anisotropic Extensions of Gamow's Liquid Drop Problem and Beyond
 11/01/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
The liquid drop (LD) model, an old problem of Gamow for the shape of atomic nuclei, has recently resurfaced within the framework of the modern calculus of variations. The problem takes the form of a nonlocal isoperimetric problem on all 3space with nonlocal interactions of Coulombic type.
In this talk, we first state and motivate the LD problem, and then summarize the state of the art for global minimizers.
We then address certain recent anisotropic variants of the LD problem in the small mass regime, with a particular focus on the minimality of the Wulff shape.
In the second half of the talk, we address a related nonlocal geometric problem based solely on competing interaction potentials of algebraic type. This problem is directly related to a wide class of selfassembly/aggregation models for interacting particle systems (eg. swarming).
This talk includes joint work with Almut Burchard (Toronto), Robin Neumayer (IAS and Northwestern), and Ihsan Topaloglu (Virginia Commonwealth).

16460

Friday 11/2 4:10 PM

Jianlin Cheng, University of Missouri

Datadriven computational modeling of 3D structures of genomes
 Jianlin Cheng, University of Missouri
 Datadriven computational modeling of 3D structures of genomes
 11/02/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
The threedimensional (3D) structure of a genome is important for genome folding, genome function, genome methylation, spatial gene regulation, and cell development, but has not been well studied due to lack of experimental techniques for genome structure determination. In this talk, I will present our largescale computational optimization methods for effectively reconstructing the 3D structure (shape) of the human genome from chromosomal conformation capturing data. The highly scalable algorithms were able to build the highestresolution structures of human chromosomes to date and one of the first structures of the entire human genome. The computational modeling enables the visualization of the previously unknown 3D shape of the genome consisting of millions of units and opens a new avenue to conduct genomics research in the 3D perspective.

16456

Monday 11/5 10:00 AM

Telma Gracias

TBA (special colloquium)
 Telma Gracias
 TBA (special colloquium)
 11/05/2018
 10:00 AM  11:00 AM
 C304 Wells Hall
No abstract available.

16451

Monday 11/5 4:10 PM

Sue Allen

MTH 103: Large Lecture Updates + ULA Management
 Sue Allen
 MTH 103: Large Lecture Updates + ULA Management
 11/05/2018
 4:10 PM  5:00 PM
 C109 Wells Hall
No abstract available.

16470

Wednesday 11/7 2:00 PM

Boris Shapiro, Stockholm University

Around Waring problem for homogeneous polynomials
 Boris Shapiro, Stockholm University
 Around Waring problem for homogeneous polynomials
 11/07/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
Waring problem for homogeneous polynomials (forms) asks to represent a given form of degree k*d as a sum of dth powers of forms of degree k. The main objective is to find a presentation with a small number of summands. The classical case going back to J.J. Sylvester deals with k=1 and binary forms. We will survey some of the results in this area and pose some elementary looking open problems. No preliminary knowledge of the topic is required

16457

Wednesday 11/7 3:00 PM

Gorapada Bera

Federer's dimension reduction argument
 Gorapada Bera
 Federer's dimension reduction argument
 11/07/2018
 3:00 PM  4:00 PM
 C304 Wells Hall
Ch. 3 of Leon Simon's book

15413

Wednesday 11/7 4:10 PM

Abhishek Mallick

Equivariant Floer Homology
 Abhishek Mallick
 Equivariant Floer Homology
 11/07/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
We will discuss constructions given by SeidelSmith and HendricksLipshitzSarkar.

15429

Wednesday 11/7 4:10 PM

Guozhen Lu, University of Connecticut; Nobody Else

Fourier analysis on hyperbolic spaces and sharp higher order HardySobolevMaz'ya inequalities
 Guozhen Lu, University of Connecticut; Nobody Else
 Fourier analysis on hyperbolic spaces and sharp higher order HardySobolevMaz'ya inequalities
 11/07/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
In this talk, we will describe some recent works on
the sharp higher order HardySobolevMaz'ya and HardyAdams inequalities on hyperbolic balls and half spaces. The relationship between the classical Sobolev inequalities and the HardySobolevMaz'ya inequalities for higher order derivatives will be established. Our main approach is to use the Fourier analysis on hyperbolic spaces and Green's function estimates.

15391

Wednesday 11/7 5:10 PM

Irina Holmes, MSU and Texas A&M

Bellman and Bollobas Functions
 Irina Holmes, MSU and Texas A&M
 Bellman and Bollobas Functions
 11/07/2018
 5:10 PM  6:00 PM
 C517 Wells Hall
No abstract available.

13346

Thursday 11/8 2:00 PM

Jonathan Campbell, Vanderbilt University

Topological Hochschild Homology and Higher Characters
 Jonathan Campbell, Vanderbilt University
 Topological Hochschild Homology and Higher Characters
 11/08/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
In this talk I'll explain how Hochschild homology and duality theory in bicategories can be used to obtain interesting Euler characteristictype invariants in a number of mathematical contexts (all of the terms in the previous sentence will be explained). A topological refinement, using THH, of this reasoning very easily yields interesting fixed point invariants, such as the Lefschetz trace and Reidemeister trace. Using this, one can show that the cyclotomic trace from algebraic Ktheory is computing fixed point invariants. Time permitting, I'll explain how zeta functions relate to the above. Prerequisites: an appetite for category theory, and a belief in, but not knowledge of, the stable homotopy category.

14362

Thursday 11/8 4:10 PM

Jared Speck

Singularity Formation in General Relativity
 Jared Speck
 Singularity Formation in General Relativity
 11/08/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
The celebrated Hawking–Penrose theorems are breakdown results for solutions to the Einstein equations of general relativity, which are a system of highly nonlinear wavelike PDEs. These theorems show that, under appropriate assumptions on the matter model, a large, open set of initial data lead to geodesically incomplete solutions. However, these theorems are “soft” in that they do not yield any information about the nature of the incompleteness, leaving open the possibilities that i) it is tied to the blowup of some invariant quantity (such as curvature) or ii) it is due to a more sinister phenomenon, such as incompleteness stemming from lack of information for how to uniquely continue the solution (this is roughly known as the formation of a Cauchy horizon). In various works, some joint with I. Rodnianski, we have obtained the first results in more than one spatial dimension that eliminate the ambiguity for an open set of initial data: for the solutions that we studied, the incompleteness is tied to the blowup of various spacetime curvature scalars along a spacelike hypersurface. Physically, this phenomenon corresponds to the stability of the Big Bang and/or Big Crunch singularities. From an analytic perspective, the main theorems are stable blowup results for quasilinear systems of elliptichyperbolic PDEs. In this talk, I will provide an overview of these results and explain how they are tied to some of the main themes of investigation by the mathematical general relativity community. I will also discuss the role of geometric and gauge considerations in the proofs, as well as intriguing connections to other problems concerning stable singularity formation.

16454

Friday 11/9 10:00 AM

Tsz Ho Chan, University of Memphis

TBA (special colloquium)
 Tsz Ho Chan, University of Memphis
 TBA (special colloquium)
 11/09/2018
 10:00 AM  11:00 AM
 C304 Wells Hall
TBA

15448

Friday 11/9 4:10 PM

Wenrui Hao, Pennsylvania State University

Computational modeling for cardiovascular risk evaluation
 Wenrui Hao, Pennsylvania State University
 Computational modeling for cardiovascular risk evaluation
 11/09/2018
 4:10 PM  5:00 PM
 1502 Engineering Building
Atherosclerosis, the leading cause of death in the United State, is a disease in which a plaque builds up inside the arteries. The LDL and HDL concentrations in the blood are commonly used to predict the risk factor for plaque growth. In this talk, I will describe a recent mathematical model that predicts the plaque formation by using the combined levels of (LDL, HDL) in the blood. The model is given by a system of partial differential equations within the plaque with a free boundary. This model is used to explore some drugs of regression of a plaque in mice, and suggest that such drugs as used for mice may also slow plaque growth in humans. Some mathematical questions, inspired by this model, will also be discussed. I will also mention briefly some related projects about abdominal aortic aneurysm (AAA) and red blood cell aggregation, which would have some potential blood biomarkers for diagnosis of AAA.

16466

Friday 11/9 4:10 PM

Jun Kitagawa, MSU

Optimal transport or: How I learned to stop worrying and grew my own shipping empire
 Jun Kitagawa, MSU
 Optimal transport or: How I learned to stop worrying and grew my own shipping empire
 11/09/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
Optimal transport, a.k.a. the MongeKantorovich problem has been an active area of mathematics recently. It is an optimization problem, but has connections to PDEs, geometry, economics, image processing, kinetics, and probability, among other areas. I will start with the discrete optimal transport problem and explain some results about existence, duality, and computation. If time permits, I will discuss the continuous framework and some other variations of the problem.

16477

Monday 11/12 1:00 PM

Joshua Ruiter, MSU

Universal Central Extensions
 Joshua Ruiter, MSU
 Universal Central Extensions
 11/12/2018
 1:00 PM  2:00 PM
 C517 Wells Hall
I'll define universal central extensions of groups, and prove a criterion for a central extension to be universal. Time permitting, I'll connect this to the 2nd algebraic Kgroup of a ring, and a certain group cohomology.

16473

Monday 11/12 3:00 PM

Leonid Chekhov, MSU

Introduction to topological recursion
 Leonid Chekhov, MSU
 Introduction to topological recursion
 11/12/2018
 3:00 PM  4:00 PM
 C304 Wells Hall
I will give a brief description of main ingredients of abstract topological recursion, which is a method for constructing correlation functions in a number of models admitting "genus", or 1/N filtration. I will show how the condition of total symmetricity of the correlation functions naturally leads to algebras of secondorder differential operators annihilating the partition function of a model. I will also discuss the transition between global and local models on a spectral curve.

16474

Tuesday 11/13 3:00 PM

Vincent Bouchard , University of Alberta

Walgebra constraints and higher Airy structures
 Vincent Bouchard , University of Alberta
 Walgebra constraints and higher Airy structures
 11/13/2018
 3:00 PM  4:00 PM
 C304 Wells Hall
Virasoro constraints are omnipresent in enumerative geometry. Recently, Kontsevich and Soibelman introduced a generalization of Virasoro constraints in the form of Airy structures. It can also be understood as an abstract framework underlying the topological recursion of Chekhov, Eynard and Orantin. In this talk I will explain how the triumvirate of Virasoro constraints, Airy structures and topological recursion can be generalized to Walgebra constraints, higher Airy structures and higher topological recursion. The resulting formalism includes as a special case the Walgebra constraints satisfied by generating functions for intersection numbers on the moduli space of rspin curves, but is much more general.
This is joint work with Gaetan Borot, Nitin Chidambaram and Dmitry Noschenko.

16476

Tuesday 11/13 4:10 PM

Shahriar Mirzadeh, MSU

Dimension estimates for the set of points with nondense orbit in homogeneous spaces
 Shahriar Mirzadeh, MSU
 Dimension estimates for the set of points with nondense orbit in homogeneous spaces
 11/13/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
Abstract: In this talk we study the set of points in a homogeneous space whose orbit escapes the complement of a fixed compact subset. We find an upper bound for the Hausdorff dimension of this set. This extends the work of Kadyrov, where he found an upper bound for the Hausdorff dimension of the set of points whose orbit misses a fixed ball of sufficiently small radius in a compact homogeneous space. We can also use our main result to produce new applications to Diophantine approximation. This is joint work with Dmitry Kleinbock.

16471

Wednesday 11/14 2:00 PM

Gorapada Bera

Federer's dimension reduction, II
 Gorapada Bera
 Federer's dimension reduction, II
 11/14/2018
 2:00 PM  4:00 PM
 C304 Wells Hall
Ch. 3 of Leon Simon's book, continued

16464

Wednesday 11/14 4:10 PM

Alexey Karapetyants

On Bergman type spaces of functions of nonstandard growth and some related questions.
 Alexey Karapetyants
 On Bergman type spaces of functions of nonstandard growth and some related questions.
 11/14/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
Abstracts: We study various Banach spaces of holomorphic functions on the unit disc and half plane. As a main question we investigate the boundedness of the corresponding holomorphic projection. We exploit the idea of V.P.Zaharyuta, V.I.Yudovich (1962) where the boundedness of the Bergman projection in Lebesgue spaces was proved using CalderonZygmund operators. We treat the cases of variable exponent Lebesgue space, Orlicz space, Grand Lebesgue space and variable exponent generalized Morrey space. The major idea is to show that the approach can be applied to a wide range of function spaces. This opens a door in a sense for introducing and studying new function spaces of Bergman type in complex analysis. We also study the rate of growth of functions near the boundary in spaces under consideration and their approximation by mollifying dilations.

15414

Wednesday 11/14 4:10 PM

Hitesh Gakhar

Künneth formulae in persistent homology
 Hitesh Gakhar
 Künneth formulae in persistent homology
 11/14/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
The classical Künneth formula provides a relationship between the homology of a product space and that of its factors. In this talk, I will briefly review persistent homology and show Künnethtype theorems for it. That is, for two different notions of products, we show how the persistent homology of a filtered product space relates to that of the factor filtered spaces.

14374

Thursday 11/15 2:00 PM

Ian Zemke, Princeton University

The stabilization distance and knot Floer homology
 Ian Zemke, Princeton University
 The stabilization distance and knot Floer homology
 11/15/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
Given a knot K in S^3, we consider the set of oriented surfaces in B^4 which bound K. A natural question is how many stabilizations and destabilizations one must perform to move from one surface to another. Similarly, one may wonder how many double point birth/deaths must occur in a regular homotopy. In this talk, we consider several metrics on the set of surfaces bounding K, based on the number of stabilizations which must occur in a stabilization sequence connecting the two surfaces, or in the minimal number of double points which appear in a generic regular homotopy. We will describe how the link Floer TQFT can be used to construct lower bounds. This is joint work with Andras Juhasz.

16467

Thursday 11/15 3:00 PM

Dapeng Zhan, MSU

Twocurve Green’s function for 2SLE
 Dapeng Zhan, MSU
 Twocurve Green’s function for 2SLE
 11/15/2018
 3:00 PM  3:50 PM
 C405 Wells Hall
A 2SLE$_\kappa$, $\kappa\in(0,8)$, is a pair of random curves $(\eta_1,\eta_2)$ in a simply connected domain $D$ connecting two pairs of boundary points such that conditioning on any curve, the other is a chordal SLE$_\kappa$ curve in a complement domain. We prove that, for the exponent $\alpha=\frac{(12\kappa)(\kappa+4)}{8\kappa}$, for any $z_0\in D$, the limit $\lim_{r\to 0^+}r^{\alpha}\mathbb{P}[\mbox{dist}(\eta_j,z_0)<r,j=1,2]$ converges to a positive number, called the twocurve Green’s function. To prove the convergence, we transform the original problem into the study of a twodimensional diffusion process, and use orthogonal polynomials to derive its transition density and invariant density.

16475

Thursday 11/15 3:00 PM

Daping Weng, MSU

More on Scattering Diagram and Theta Functions
 Daping Weng, MSU
 More on Scattering Diagram and Theta Functions
 11/15/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
Abstract: I will continue the discussion on scattering diagram and theta functions and relate them to the classical cluster theories. I will sketch GrossHackingKeelKontsevich’s proofs of positive Laurent phenomenon, sign coherence, and a weak version of the cluster duality conjecture.

15392

Friday 11/16 2:10 PM

Dominique Maldague, UC Berkeley

TBA
 Dominique Maldague, UC Berkeley
 TBA
 11/16/2018
 2:10 PM  3:00 PM
 C304 Wells Hall
No abstract available.

15446

Friday 11/16 4:10 PM

Jun Song, University of Illinois at UrbanaChampaign

Spectral and Statistical Analyses of Nucleosome Positioning: New Answers to Old Questions
 Jun Song, University of Illinois at UrbanaChampaign
 Spectral and Statistical Analyses of Nucleosome Positioning: New Answers to Old Questions
 11/16/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
Nucleosomes form the fundamental building blocks of eukaryotic
chromatin, and previous attempts to understand the principles
governing their genomewide distribution have spurred much interest
and debate in biology. In particular, the precise role of DNA sequence
in shaping local chromatin structure has been controversial.
In this talk, I will described categorical spectral analysis methods
and statistical physics approaches for rigorously quantifying the
contribution of hithertodebated sequence features to three
distinct aspects of genomewide nucleosome landscape: occupancy,
translational positioning, and rotational positioning.

17480

Monday 11/19 1:00 PM

Charlotte Ure, MSU

The Brauer Class Associated to the Binary Cubic Generic Clifford Algebra
 Charlotte Ure, MSU
 The Brauer Class Associated to the Binary Cubic Generic Clifford Algebra
 11/19/2018
 1:00 PM  2:00 PM
 C517 Wells Hall
The Clifford algebra associated to a quadratic form is a classical algebraic object with many applications. Its definition can be generalized to forms of higher degree. In the case of a binary cubic form, the center of the associated Clifford algebra is isomorphic to the affine coordinate ring of an elliptic curve. Furthermore, it is an Azumaya algebra over its center and thus it defines an element in the Brauer group. We study this phenomenon in families and show that the universal class (the class of the binary cubic generic Clifford algebra) is never trivial. This is joint work with Rajesh Kulkarni.

16480

Monday 11/19 5:15 PM

Andrew Krause, MSU

MTH 133 Labs: Classroom Research and Future Directions
 Andrew Krause, MSU
 MTH 133 Labs: Classroom Research and Future Directions
 11/19/2018
 5:15 PM  6:00 PM
 C109 Wells Hall
No abstract available.

16472

Wednesday 11/21 12:30 PM

Keshav Sutrave

EellsSampson's Theorem
 Keshav Sutrave
 EellsSampson's Theorem
 11/21/2018
 12:30 PM  2:00 PM
 C304 Wells Hall
1964 classic existence result for harmonic maps with nonpositively curved target manifold, using heat flow method.

15415

Wednesday 11/21 4:10 PM

Gorapada Bera

Introduction to SeibergWitten Invariants
 Gorapada Bera
 Introduction to SeibergWitten Invariants
 11/21/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
After a brief introduction of SeibergWitten equations on closed smooth four manifolds, we will see how moduli space of solutions leads to an oriented compact manifold and a topological invariant (SeibergWitten Invariant) for the four manifold. Then for the purpose of computation of this invariant on Kähler manifolds, we will rewrite the equation in terms of complex geometry and see for most of the Kähler Surfaces the answer will be in terms of algebraic geometric criterion of the surface. Most of the technical details will be omitted but some brief sketches will be there. I will follow John Morgan's Book on Seiberg Witten equations.

17484

Tuesday 11/27 11:00 AM

Zhenge Zhang, UC Riverside

Localization via positivity and large deviations of the Lyapunov exponent
 Zhenge Zhang, UC Riverside
 Localization via positivity and large deviations of the Lyapunov exponent
 11/27/2018
 11:00 AM  12:00 PM
 C304 Wells Hall
In this talk, I will introduce the role of a dynamical object, the Lyapunov exponent, in
the spectral analysis of onedimensional ergodic Schrodinger operators. I will show how to obtain
Anderson Localization via positivity and Large deviations of the Lyapunov exponent.
I will mainly focus on the onedimensional Anderson model, where a relatively simple proof
of spectral localization and exponentially dynamical localization may be obtained.

16452

Tuesday 11/27 1:30 PM

Darryl Yong, Harvey Mudd College

Active Learning 2.0: Being Intentionally Inclusive
 Darryl Yong, Harvey Mudd College
 Active Learning 2.0: Being Intentionally Inclusive
 11/27/2018
 1:30 PM  3:00 PM
 252 EH
Active learning has many documented benefits both for students and instructors. Moreover, there is increasing evidence that it disproportionately benefits women, students of color, and students who were previously denied the same learning opportunities as others. However, the empirical evidence for this disproportionate benefit doesn't explain why it happens, nor does it guarantee that all students will benefit from active learning. In fact, my own experience with active learning is that it is difficult to do well and sometimes it can have detrimental effects on students if we're not careful. So, we should aim not just for active learning, but learning that is both active and inclusive. We'll discuss some principles and practical strategies for making active learning more inclusive.

16463

Tuesday 11/27 4:00 PM

Kesong Yan, MSU and Guangxi University of Finance and Economics

Entropy and Complexity of topological dynamical systems
 Kesong Yan, MSU and Guangxi University of Finance and Economics
 Entropy and Complexity of topological dynamical systems
 11/27/2018
 4:00 PM  5:00 PM
 C304 Wells Hall
Abstract: In this talk, we will review some results about the topological entropy and complexity for topological dynamical systems.

16479

Wednesday 11/28 2:00 PM

Thomas Walpuski

Quantitative Stratification and the Regularity of Harmonic Maps (part I)
 Thomas Walpuski
 Quantitative Stratification and the Regularity of Harmonic Maps (part I)
 11/28/2018
 2:00 PM  3:30 PM
 C304 Wells Hall
CheegerNaber's 2011 paper (Published in CPAM, 2013).

16465

Wednesday 11/28 4:10 PM

Alexander Volberg, MSU

Improving L^1 Poincar\'e inequality on Hamming cube
 Alexander Volberg, MSU
 Improving L^1 Poincar\'e inequality on Hamming cube
 11/28/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
L^1 Poincar\'e inequality on hypercube is related to many interesting questions in random graph theory (like Margoulis graph connectivity theorem, e.g.). The sharp constant is unknown, but I will show how to improve the previously known constant \pi/2 obtained by Ben Efraim and LustPiquard by using noncommutative harmonic analysis. The approach will be probabilistic and luckily commutative. For Gaussian space the constant is known, it is \sqrt{\pi/2}, and the short proof belong to MaureyPisier.

15416

Wednesday 11/28 4:10 PM

Brandon Bavier

Generalizing Alternating Knots
 Brandon Bavier
 Generalizing Alternating Knots
 11/28/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
One of the nicer properties a knot can have is to be alternating. These knots tend to be easy to work with, and can give us several nice results about the whole class. Unfortunately, many knots are not alternating, causing general proofs about them to be difficult at best. In this talk, we will take a look at a couple of different ways we can broaden the class of alternating knots, and see what we can get from these different definitions of alternating.

15380

Thursday 11/29 2:00 PM

Dominic Culver, University of Illinois UrbanaChampaign

Towards a counter example of the telescope conjecture
 Dominic Culver, University of Illinois UrbanaChampaign
 Towards a counter example of the telescope conjecture
 11/29/2018
 2:00 PM  3:00 PM
 C304 Wells Hall
The telescope conjecture is the only remaining Ravenel conjecture to remain unsolved. In this talk, I will give a review of the chromatic perspective on stable homotopy theory and motivate the telescope conjecture. I will then proceed to sketch Mahowald’s proof of the height 1 telescope conjecture for 2local spectra. Time permitting, I will describe work in progress with Beaudry, Behrens, Bhattacharya, and Xu on using the tmfresolution of the BhattacharyaEgger spectrum to find a counter example to the height 2 telescope conjecture.

15443

Thursday 11/29 3:00 PM

Greg Muller, University of Oklahoma

Scattering diagrams of marked surfaces
 Greg Muller, University of Oklahoma
 Scattering diagrams of marked surfaces
 11/29/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
Every cluster algebra has an associated 'scattering diagram': an affine space endowed with a (possibly very complicated) collection of 'walls'. The structure of this scattering diagram encodes essential information about the cluster algebra's exchange graph, Laurent coefficients, and theta functions. In this talk, I will discuss an ongoing project with Nathan Reading and Shira Viel to construct a scattering diagram associated to a triangulable marked surface. The affine space may be identified with the set of certain `measured laminations' on the surface, and the walls may be identified with certain forbidden subgraphs embedded in the surface, which we call `barricades'.

17485

Thursday 11/29 3:00 PM

Soukaina Douissi , Cadi Ayyad University, Marrakech, Morocco

Meanfield anticipated BSDEs driven by fractional Brownian motion and related stochastic control problem
 Soukaina Douissi , Cadi Ayyad University, Marrakech, Morocco
 Meanfield anticipated BSDEs driven by fractional Brownian motion and related stochastic control problem
 11/29/2018
 3:00 PM  3:50 PM
 C405 Wells Hall
In this talk, we introduce a new type of BSDEs, we call it meanfield anticipated backward stochastic differential equations (MFBSDEs, for short) driven by a fractional Brownian motion with Hurst parameter H>1/2. We will show that it's possible to prove the existence and uniqueness of this new type of BSDEs using two different approaches. Then, we will present a comparison theorem for such BSDEs. Finally, as an application of this type of equations, a related stochastic optimal control problem is studied.
This is a joint work with Yufeng Shi and Jiaqiang Wen : Institute for Financial Studies and School of Mathematics, Shandong University, Jinan 250100, China.

17487

Friday 11/30 10:20 AM

Estrella Johnson, Virginia Tech

Taking an Instructional Innovation to Scale: Characterizing, Supporting, and Evaluating InquiryOriented Instruction
 Estrella Johnson, Virginia Tech
 Taking an Instructional Innovation to Scale: Characterizing, Supporting, and Evaluating InquiryOriented Instruction
 11/30/2018
 10:20 AM  11:10 AM
 C304 Wells Hall
Inquiryoriented instruction has shown promise in regards to many features of student success, including conceptual understanding, affective gains, and persistence in STEM degrees. However, instructional change is difficult (especially at scale) and the research literature has documented a number of challenges instructors face when shifting their instructional practice. During this talk I will provide a characterization of inquiryoriented instruction; discuss an instructional support model that was developed to support inquiryoriented instruction in undergraduate mathematics courses; and present preliminary evaluation findings, drawing on a national sample of content assessment data, collected from 513 students at 46 different institutions. Analysis of this assessment data revealed no difference in the performance of men and women in the comparison sample; however, under the inquiryoriented treatment, a gender performance difference was present – with men outperforming women. In an effort to understand this finding, I present related research literature on gendered experiences in collaborative settings and our preliminary analysis into the experiences of our students in these inquiryoriented courses.

16461

Friday 11/30 4:10 PM

Rongrong Lin , Sun Yatsen University

Machine Learning with Reproducing Kernels
 Rongrong Lin , Sun Yatsen University
 Machine Learning with Reproducing Kernels
 11/30/2018
 4:10 PM  5:00 PM
 C517 Wells Hall
Reproducing kernel Hilbert spaces (RKHSs) are Hilbert spaces of functions on which point evaluation functionals are continuous. Thanks to the existence of an inner product, RKHSs are wellunderstood in functional analysis. Successful and important machine learning methods based on RKHSs include support vector machines, regularization networks and kernelbased approximation.
In the past decade, there has been emerging interest in constructing reproducing kernel Banach spaces (RKBSs) for applied and theoretical purposes for instance sparse approximation. Recently, we propose a generic definition of RKBS and a framework of constructing RKBSs that unifies existing constructions in the literature, and leads further to new RKBSs. As a byproduct, the space C([0,1]) of all continuous functions on the interval [0,1] is an RKBS.
Motivated by sparse multitask learning, we constructed a class of vectorvalued RKBSs with the l1 norm based on multitask admissible kernels. The relaxed linear representer theorem holds for regularization networks in the obtained spaces if and only if the Lebesgue constant of kernels is uniformly bounded. A class of translationinvariant kernels of limited smoothness admissible for construction are given. Numerical experiments demonstrate the advantages of the proposed construction and regularization models.
This talk is based on two joint papers with Prof. Guohui Song (Clarkson University), Haizhang Zhang (Sun Yatsen University), and Jun Zhang (University of Michigan).

17488

Tuesday 12/4 3:00 PM

Kesong Yan, MSU and Guangxi University of Finance and Economics

Entropy and Complexity of topological dynamical systems
 Kesong Yan, MSU and Guangxi University of Finance and Economics
 Entropy and Complexity of topological dynamical systems
 12/04/2018
 3:00 PM  4:00 PM
 C304 Wells Hall
Abstract: In this talk, we will review some results about the topological entropy and complexity for topological dynamical systems.
This is a continuation of the talk given in the last week.

17481

Wednesday 12/5 2:00 PM

Thomas Walpuski, MSU

Quantitative Stratification and the Regularity of Harmonic Maps (part II)
 Thomas Walpuski, MSU
 Quantitative Stratification and the Regularity of Harmonic Maps (part II)
 12/05/2018
 2:00 PM  3:30 PM
 C304 Wells Hall
Continuation of last week's talk.

15417

Wednesday 12/5 4:10 PM

Zhe Zhang

Bott's paper about geometric quantization
 Zhe Zhang
 Bott's paper about geometric quantization
 12/05/2018
 4:10 PM  5:00 PM
 A202 Wells Hall
Raoul Bott  "On some recent interactions between mathematics and physics" (1985).
It is a mathematical point of view about how quantum phenomena naturally arises when we use Feynman’s idea of path integral and try to give a rigorous definition of the electromagnetic potential. This in turn gives us a new interpretation of a symplectic manifold as space of flat connections over a Riemann surface.

15397

Thursday 12/6 2:00 PM

Lev TovstopyatNelip , Boston College

The transverse invariant and braid dynamics
 Lev TovstopyatNelip , Boston College
 The transverse invariant and braid dynamics
 12/06/2018
 2:00 PM  2:50 PM
 C304 Wells Hall
Let K be a link braided about an open book (B,p) supporting a contact manifold (Y,x). K and B are naturally transverse links. We prove that the hat version of the transverse link invariant defined by Baldwin, VelaVick and Vertesi is nonzero for the union of K with B. As an application, we prove that the transverse invariant of any braid having fractional Dehn twist coefficient greater than one is nonzero. We discuss geometric consequences and future directions.

17483

Thursday 12/6 3:00 PM

Daping Weng, MSU

More on Scattering Diagram and Theta Functions
 Daping Weng, MSU
 More on Scattering Diagram and Theta Functions
 12/06/2018
 3:00 PM  4:00 PM
 C117 Wells Hall
I will continue the discussion on scattering diagram and theta functions and relate them to the classical cluster theories. I will sketch GrossHackingKeelKontsevich’s proofs of positive Laurent phenomenon, sign coherence, and a weak version of the cluster duality conjecture.

17486

Friday 12/7 12:00 PM

Corey Drake and Kimberly Jansen, MSU and University of Virginia

Novice Elementary Teachers’ Enactment of Ambitious Instruction in Mathematics: Challenges and Responses
 Corey Drake and Kimberly Jansen, MSU and University of Virginia
 Novice Elementary Teachers’ Enactment of Ambitious Instruction in Mathematics: Challenges and Responses
 12/07/2018
 12:00 PM  1:00 PM
 133F Erick
Substantial work in teacher education over the past several years has focused on elaborating and understanding the construct of ambitious instruction. While research on ambitious instruction has included detailed descriptions of ambitious teaching practices and the ways in which teacher education experiences are intended to promote the development of these practices, less research has investigated the conditions under which teachers, particularly novice teachers, are more or less likely to enact ambitious instruction (though Thompson, Windschitl, & Braaten, 2013, provide an exception). In this presentation, we will share the challenges to ambitious instruction identified by a group of 61 novice elementary teachers from four different teacher preparation programs. We will also share four types of responses novices had to these challenges and the implications of these responses for the enactment of ambitious instruction.
Thompson, J., Windschitl, M., & Braaten, M. (2013). Developing a theory of ambitious earlycareer teacher practice. American Education Research Journal, 50(3), 574615.

17482

Friday 12/7 4:10 PM

Ming Tse Paul Laiu, Oak Ridge National Laboratory

A Positive Asymptotic Preserving Scheme for Linear Kinetic Transport Equations
 Ming Tse Paul Laiu, Oak Ridge National Laboratory
 A Positive Asymptotic Preserving Scheme for Linear Kinetic Transport Equations
 12/07/2018
 4:10 PM  5:00 PM
 1502 Engineering Building
We present a positive and asymptotic preserving numerical scheme for solving linear kinetic, transport equations that relax to a diffusive equation in the limit of infinite scattering.
The proposed scheme is developed using a standard spectral angular discretization and a classical micromacro decomposition.
The three main ingredients are a semiimplicit temporal discretization, a dedicated finite difference spatial discretization, and realizability limiters in the angular discretization.
Under mild assumptions, the scheme becomes a consistent numerical discretization for the limiting diffusion equation when the scattering crosssection tends to infinity.
The scheme also preserves positivity of the particle concentration on the spacetime mesh and therefore fixes a common defect of spectral angular discretizations.
The scheme is tested on wellknown benchmark problems and gives promising results.

16469

Thursday 12/13 4:10 PM

Noam Elkies, Harvard University

Sphere Packing from Cerium to Viazovska
 Noam Elkies, Harvard University
 Sphere Packing from Cerium to Viazovska
 12/13/2018
 4:10 PM  5:00 PM
 C304 Wells Hall
The sphere packing problem in dimension $n$ asks:
How densely can one pack identical Euclidean balls in $\mathbb{R}^n$ with
disjoint interiors? We review some of this problem's history and
connections with various areas of mathematics and science.
Some special values of $n$, notably $8$ and $24$, allow for remarkably
tight and symmetrical configurations that have long been suspected
to be the densest possible in those dimensions. We conclude with the
series of recent results culminating with Viazovska's breakthrough that
led to the solution of the sphere packing problem for $n=8$ and $n=24$.
