Talk_id  Date  Speaker  Title 
18593

Thursday 8/29 2:00 PM

Chris Gerig, Harvard University

Probing 4manifolds with nearsymplectic forms
 Chris Gerig, Harvard University
 Probing 4manifolds with nearsymplectic forms
 08/29/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
Most closed 4manifolds do not admit symplectic forms, but most admit "nearsymplectic forms", certain closed 2forms which are symplectic outside of a collection of circles. This provides a gateway from the symplectic world to the nonsymplectic world. I will first briefly sketch a geometric interpretation of the SeibergWitten invariants in terms of Jholomorphic curves that are compatible with the nearsymplectic form. Although the SeibergWitten invariants don't apply to (potentially exotic) 4spheres, nor do these spheres admit nearsymplectic forms, there is still a way to bring in nearsymplectic techniques.

19616

Tuesday 9/3 12:00 PM


Organizational meeting

 Organizational meeting
 09/03/2019
 12:00 PM  1:30 PM
 C304 Wells Hall
No abstract available.

19605

Wednesday 9/4 3:00 PM

Bruce Sagan, MSU

An introduction to qanalogues
 Bruce Sagan, MSU
 An introduction to qanalogues
 09/04/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
The theory of qanalogues is important in both combinatorics and the study of hypergeometric series. Roughly speaking, the qanalogue of a mathematical object (which could be a number or a theorem or ...) is another object depending on a parameter q which reduces to the original object when q=1. This talk will be a gentle introduction to qanalogues. No background will be assumed.

19603

Thursday 9/5 11:00 AM

Ramis Movassagh, IBM

Proof of averagecase #P hardness of random circuit sampling with some robustness, and a protocol for blind quantum computation
 Ramis Movassagh, IBM
 Proof of averagecase #P hardness of random circuit sampling with some robustness, and a protocol for blind quantum computation
 09/05/2019
 11:00 AM  12:00 PM
 C304 Wells Hall
A oneparameter unitaryvalued interpolation between any two unitary matrices (e.g., quantum gates) is constructed based on the Cayley transformation. We prove that this path induces probability measures that are arbitrarily close to the Haar measure and prove the simplest known averagecase # P hardness of random circuit sampling (RCS). RCS is the task of sampling from the output distribution of a quantum circuit whose local gates are random Haar unitaries, and is the lead candidate for demonstrating quantum supremacy in the "noisy intermediate scale quantum (NISQ)" computing era. Here we also prove exp(Θ(n^4 )) robustness with respect to additive error. This overcomes issues that arise for extrapolations based on the truncations of the power series representation of the exponential function. (Dis)Proving the quantum supremacy conjecture requires an extension of this analysis to noise that is polynomially small in the system's size. This remains an open problem. Lastly, an efficient and private protocol for blind quantum computation is proposed that uses the Cayley deformations proposed herein for encryption. This is an efficient protocol that only requires classical communication between Alice and Bob.
** The talk is selfcontained and does not require any prereq beyond basic linear algebra (e.g, knowing what a unitary matrix is).

19602

Thursday 9/5 2:00 PM

Alex Waldron, Michigan State University

$G_2$instantons on the 7sphere
 Alex Waldron, Michigan State University
 $G_2$instantons on the 7sphere
 09/05/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
I'll discuss a forthcoming paper studying families of $G_2$instantons on $S^7$, focusing on those which are obtained by pulling back asd instantons on $S^4 $ via the quaternionic Hopf fibration. In the charge1 case this yields a smooth and complete 15dimensional family. The situation for higher charge is more complicated, but we are able to compute all the infinitesimal deformations.

19615

Thursday 9/5 3:00 PM

Erik Bates, UC Berkeley

Localization of Gaussian disordered systems at low temperature
 Erik Bates, UC Berkeley
 Localization of Gaussian disordered systems at low temperature
 09/05/2019
 3:00 PM  3:50 PM
 C405 Wells Hall
The fundamental premise of statistical mechanics is that a physical system's state is random according to some probability measure, which is determined by the various forces of interaction between the system's constituent particles. In the ``disordered" setting, these interactions are also random (meant to capture the effect of a random medium), meaning the probability measure is itself a random object. This setting includes several of the models most widely studied by mathematical physicists, such as the Random Energy Model, the SherringtonKirkpatrick spin glass, and directed polymers. The most intriguing part of their phase diagrams occurs at low temperature, when the measure concentrates, or "freezes", on energetically favorable states. In general, quantifying this phenomenon is especially challenging, in large part due to the extra layer of randomness created by the disorder. This talk will describe recent progress on this question, leading us to some conjectures on further open problems. (Joint work with Sourav Chatterjee)

18596

Thursday 9/5 4:10 PM

Eric Zaslow, Northwestern University

Applications of Constructible Sheaves to Symplectic Topology
 Eric Zaslow, Northwestern University
 Applications of Constructible Sheaves to Symplectic Topology
 09/05/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
My goal is to explain a few applications of constructible sheaves to symplectic topology through examples that we can calculate together on the board.
In particular, I would like to explain how sheaves relate to: 1) Legendrian knot invariants, 2) cluster varieties, 3) nonfillability results for Legendrian surfaces.

19623

Monday 9/9 4:00 PM

AMS Student Chapter, MSU

Potluck and introduction
 AMS Student Chapter, MSU
 Potluck and introduction
 09/09/2019
 4:00 PM  5:00 PM
 C204 Wells Hall
Come learn what AMS is all about, what events are scheduled for this year, and meet your student community! This event is for ALL members, new and returning.
We'd love it if you could bring a snack or dish to share if you're able to.
We are also looking to fill two eboard positions: secretary and treasurer! We will discuss more about these positions on Tuesday and would love to hear from you if you're interested.

19620

Monday 9/9 4:10 PM

Rachael Lund + Andy Krause, MSU

Accommodations for students with RCPD VISAs
 Rachael Lund + Andy Krause, MSU
 Accommodations for students with RCPD VISAs
 09/09/2019
 4:10 PM  5:00 PM
 C109 Wells Hall
We talk as a group about how we are appropriately accommodating students with VISAs, with a specific emphasis on groupworkexempt accommodations.

19613

Monday 9/9 4:30 PM

Ioannis Zachos, Michigan State

Gröbner basis and the Ideal Membership problem
 Ioannis Zachos, Michigan State
 Gröbner basis and the Ideal Membership problem
 09/09/2019
 4:30 PM  5:30 PM
 C304 Wells Hall
We know from the Hilbert Basis Theorem that any ideal in a polynomial ring over a field is finitely generated. However, there remains question as to the best generators to choose to describe the ideal. Are there generators for a polynomial ideal $I$ that make it easy to see if a given polynomial $f$ belongs to $I$? For instance, does $2x^2z^2+2xyz^2+2xz^3+z^31$ belong to $I=(x+y+z, xy+xz+yz, xyz−1)$? Deciding if a polynomial is in an ideal is called the Ideal Membership Problem. In polynomial rings of one variable, we use long division of polynomials to solve this problem. There is a corresponding algorithm for $K[x_1,\ldots, x_n]$, but because there are multiple variables and multiple divisors, the remainder of the division is not unique. Hence a remainder of $0$ is a sufficient condition, but not a necessary condition, to determine ideal membership. However, if we choose the correct divisors, then the remainder is unique regardless of the order of the divisors. These divisors are called a Gröbner basis. In our talk we will define the Gröbner basis and see how it solves the Ideal Membership Problem.

19617

Tuesday 9/10 11:00 AM

Brent Nelson, MSU

Introduction to Free Products of von Neumann Algebras
 Brent Nelson, MSU
 Introduction to Free Products of von Neumann Algebras
 09/10/2019
 11:00 AM  12:00 PM
 C304 Wells Hall
In this learning seminar, I will give an introduction to the free product construction for von Neumann algebras, which is the direct analogue of a free product for groups. Moreover, it defines the noncommutative independence relation most frequently used in free probability. No prior knowledge of von Neumann algebras will be necessary.

19624

Wednesday 9/11 3:00 PM

Bruce Sagan, MSU

Combinatorial interpretations of Lucas analogues
 Bruce Sagan, MSU
 Combinatorial interpretations of Lucas analogues
 09/11/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
The Lucas sequence is a sequence of polynomials in $s,t$ defined recursively by $\{0\}=0$, $\{1\}=1$, and $\{n\}=s\{n1\}+t\{n2\}$ for $n\ge2$. On specialization of $s$ and $t$ one can recover the Fibonacci numbers, the nonnegative integers, and the $q$integers $[n]_q$. Given a quantity which is expressed in terms of products and quotients of nonnegative integers, one obtains a Lucas analogue by replacing each factor of $n$ in the expression with $\{n\}$. It is then natural to ask if the resulting rational function is actually a polynomial in $s$ and $t$ and, if so, what it counts. Using lattice paths, we give combinatorial models for Lucas analogues of binomial coefficients. We also consider Catalan numbers and their relatives, such as those for finite Coxeter groups. This is joint work with Curtis Bennett, Juan Carrillo, and John Machacek.

17489

Wednesday 9/11 4:10 PM

Marcelo Disconzi, Vanderbilt University

Rough solutions to the threedimensional compressible Euler equations with vorticity and entropy
 Marcelo Disconzi, Vanderbilt University
 Rough solutions to the threedimensional compressible Euler equations with vorticity and entropy
 09/11/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
We prove a series of intimately related results tied to the regularity and geometry of solutions to the threedimensional compressible Euler equations.
The solutions are allowed to have nontrivial vorticity and entropy, and an arbitrary equation of state with positive sound speed. The central theme is that under low regularity assumptions on the initial data, it is possible to avoid, at least for short times, the formation of shocks. Our main result is that the time of classical existence can be controlled under low regularity assumptions on the part of the initial data associated with propagation of sound waves in the fluid. Such low regularity assumptions are in fact optimal. To implement our approach, we derive several results of independent interest: (i) sharp estimates for the acoustic geometry, which in particular capture how the vorticity and entropy interact with the sound waves; (ii) Strichartz estimates for quasilinear sound waves coupled to vorticity and entropy; (iii) Schauder estimates for the transportdivcurlpart of the systems. Compared to previous works on low regularity, the main new feature of our result is that the quasilinear PDE system under study exhibit multiple speeds of propagation. In fact, this is the first result of its kind for a system with multiple characteristic speeds. An interesting feature of our proof is the use of techniques that originated in the study of the vacuum Einstein equations in general relativity.

19606

Thursday 9/12 11:00 AM

Mike Hartglass, Santa Clara University

Free products of finitedimensional von Neumann algebras
 Mike Hartglass, Santa Clara University
 Free products of finitedimensional von Neumann algebras
 09/12/2019
 11:00 AM  12:00 PM
 C304 Wells Hall
I will present joint work with Brent Nelson, where we classify the structure of free products of von Neumann algebras equipped with arbitrary states. Our techniques use our other joint work of assigning a von Neumann algebra associated to a weighted graph. I will discuss this work and how it leads to computing finitedimensional free products.

19635

Thursday 9/12 2:00 PM

Honghao Gao, MSU

Augmentations and sheaves for links
 Honghao Gao, MSU
 Augmentations and sheaves for links
 09/12/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
We study two different invariants of framed oriented links. Augmentations are rank one representations of a noncommutative algebra, whose definition is motivated by Floer homology. Sheaves in microlocal theory can be thought of as generalizations of link group representations. We will demonstrate two constructions going back and forth between these invariants. We will also tell a motivating story behind the scene, using SFT and microlocalization correspondence in symplectic topology.

19625

Friday 9/13 4:10 PM

Jiangguo (James) Liu, Colorado State University

Developing Finite Element Solvers for Poroelasticity in the Twofield Approach
 Jiangguo (James) Liu, Colorado State University
 Developing Finite Element Solvers for Poroelasticity in the Twofield Approach
 09/13/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
This talk presents results from our recent efforts for reviving the 2field approach (fluid pressure and solid displacement) for numerically solving poroelasticity problems. We choose quadrilateral and hexahedral meshes for spatial discretization since they are equally flexible in accommodating complicated domain geometry but involve less unknowns, compared to simplicial meshes. The Darcy equation is solved for fluid pressure by the novel weak Galerkin finite element methods, which establish the discrete weak gradient and numerical velocity in the ArbogastCorrea spaces. The elasticity equation is solved for solid displacement by the enriched Lagrangian elements, which were motivated by the BernardiRaugel elements for Stokes flow. These two types of finite elements are coupled through the implicit Euler temporal discretization to solve poroelasticity. Numerical experiments on benchmarks will be presented to show that the new solvers are lockingfree. Implementation on deal.II will be discussed also. This talk is based on a series of joint work with several collaborators.

19610

Monday 9/16 4:30 PM

Chuangtian Guan, MSU

P.D. rings with a view towards Crystals
 Chuangtian Guan, MSU
 P.D. rings with a view towards Crystals
 09/16/2019
 4:30 PM  5:30 PM
 C304 Wells Hall
In this talk we will define P.D. rings, which are triples consisting a ring, an ideal of the ring and a map on an ideal mimicking $x^n/n!$. We will give some examples of P.D. rings and discuss their properties. Then we will use the P.D. structures to define the crystalline site of schemes and crystals. If time admits we will talk about some examples of crystals and explain why we care about them.

19634

Tuesday 9/17 12:00 PM

Dongsoo Lee, MSU

Morse homology
 Dongsoo Lee, MSU
 Morse homology
 09/17/2019
 12:00 PM  1:00 PM
 C304 Wells Hall
First meeting of seminar on instanton Floer homology.

19636

Tuesday 9/17 3:00 PM

Honghao Gao, MSU

Legendrian knots and augmentation varieties
 Honghao Gao, MSU
 Legendrian knots and augmentation varieties
 09/17/2019
 3:00 PM  4:00 PM
 C204A Wells Hall
We begin with a gentle introduction to Legendrian knot and its invariant theory. We will define the ChekanovEliashberg different graded algebra and augmentations associated to the dga. We also present an example where the augmentation variety is a cluster variety.

19642

Thursday 9/19 10:00 AM

Nick Rekuski, MSU

Perfectoid Fields and Tilting
 Nick Rekuski, MSU
 Perfectoid Fields and Tilting
 09/19/2019
 10:00 AM  11:30 AM
 C329 Wells Hall
In this talk we will introduce perfectoid fields and tilting. Perfectoid fields provide the the correct base scheme for perfectoid spaces. Tilting is a fundamental tool that will let us lift characteristic $0$ results to characteristic $p$ results. For example, if $K$ is a characteristic $0$ perfectoid field and $K^{\flat}$ is a tilt of $K$ then $K^{\flat}$ is a characteristic $p$ field; $K^{\circ}/K^{\circ\circ}\cong K^{\flat \circ}/K^{\flat\circ\circ}$; if $[L:K]$ is finite then $[L^{\flat}:K^{\flat}]=[L:K]$ (in particular, $L$ is perfectoid); and there is an equivalence of categories between finite étale covers of $K$ and finite étale covers of $K^{\flat}$ via $L\mapsto L^{\flat}$.
This talk will not require any material beyond firstyear graduate algebra. However, the sophistication required may be higher. To make this talk as accessible as possible, we will include numerous examples.

19607

Thursday 9/19 11:30 AM

Scott Atkinson, University of California, Riverside

Tracial stability and related topics in operator algebras
 Scott Atkinson, University of California, Riverside
 Tracial stability and related topics in operator algebras
 09/19/2019
 11:30 AM  12:30 PM
 C304 Wells Hall
We will discuss the notion of tracial stability for operator algebras. Morally, an algebra A is tracially stable if approximate homomorphisms on A are near honest homomorphisms on A. We will discuss several examples and nonexamples of tracially stable algebras including certain graph products (simultaneous generalization of free and tensor products) of C*algebras. We will also discuss properties closely related to tracial stability that provide new characterizations of amenability. Parts of this talk are based on joint work with Srivatsav Kunnawalkam Elayavalli.

18587

Thursday 9/19 4:10 PM

Aaron Naber, Northwestern University

Introduction to the Energy Identity for YangMills
 Aaron Naber, Northwestern University
 Introduction to the Energy Identity for YangMills
 09/19/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
In this talk we give an introduction to the analysis of the YangMills equation in higher dimensions. In particular, when studying sequences of solutions we will study the manner in which blow up can occur, and how this blow up may be understood through the classical notions of the defect measure and bubbles. The energy identity is an explicit conjectural relationship relating the energy density of the defect measure at a point to the bubbles which occur at that point. This talk is introductory and we will spend most of our time understanding the words of this abstract. If time permits we will briefly discuss the ideas needed to prove this conjecture and the related $W^{2,1}$conjecture. The work is joint with Daniele Valtorta.

19637

Friday 9/20 4:10 PM

Jeanne Wald, MSU

Special event: Introductions to Ongoing Undergraduate MTH and STT Research Projects
 Jeanne Wald, MSU
 Special event: Introductions to Ongoing Undergraduate MTH and STT Research Projects
 09/20/2019
 4:10 PM  5:30 PM
 C304 Wells Hall
Exchange and MSU Student Research Teams will give brief introductions to their research projects.

19631

Monday 9/23 4:30 PM

Nick Rekuski, Michigan State

Splitting Criteria for Vector Bundles on $\mathbb{P}^n$
 Nick Rekuski, Michigan State
 Splitting Criteria for Vector Bundles on $\mathbb{P}^n$
 09/23/2019
 4:30 PM  5:30 PM
 C304 Wells Hall
Grothendieck's Theorem says that any vector bundle on $\mathbb{P}^1$ can be decomposed as a finite sum of line bundles. In this talk, we will discuss a generalization of this theorem: Horrocks Splitting Criterion. This criterion completely describes when a vector bundle on $\mathbb{P}^n$ splits as a sum of line bundles. We will then discuss an open conjecture of Hartshorne. If time permits, we will also consider the similar question of classifying when a vector bundle on $\mathbb{P}^n$ decompose as line bundles and twists of the tangent bundle.

19651

Tuesday 9/24 12:00 PM

Honghao Gao, MSU

More on Morse homology
 Honghao Gao, MSU
 More on Morse homology
 09/24/2019
 12:00 PM  1:00 PM
 C117 Wells Hall
No abstract available.

19647

Tuesday 9/24 3:00 PM

Honghao Gao, MSU

Legendrian knots and augmentation varieties
 Honghao Gao, MSU
 Legendrian knots and augmentation varieties
 09/24/2019
 3:00 PM  4:00 PM
 C204A Wells Hall
We begin with a gentle introduction to Legendrian knot and its invariant theory. We will define the ChekanovEliashberg different graded algebra and augmentations associated to the dga. We also present an example where the augmentation variety is a cluster variety.

19644

Wednesday 9/25 3:00 PM

Bruce Sagan, MSU

Lucas atoms
 Bruce Sagan, MSU
 Lucas atoms
 09/25/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
We introduce a powerful algebraic method for proving that Lucas analogues are polynomials with nonnegative coefficients. In particular, we factor a Lucas polynomial as
$\{n\}=\prod_{dn} P_d(s,t)$, where we call the polynomials $P_d(s,t)$ Lucas atoms.
This permits us to show that the Lucas analogues of the FussCatalan and FussNarayana numbers for all irreducible Coxeter groups are polynomials in $s,t$.
Using gamma expansions, a technique which has recently become popular in combinatorics and geometry, one can show that the Lucas atoms have a close relationship with cyclotomic polynomials $\Phi_d(q)$.
Certain results about the $\Phi_d(q)$ can then be lifted to Lucas atoms.
In particular, one can prove analogues of theorems of Gauss and Lucas, deduce reduction formulas, and evaluate the $P_d(s,t)$ at various specific values of the variables. This is joint work with Jordan Tirrell based on an idea of Richard Stanley.

19650

Thursday 9/26 10:00 AM

Chuangtian Guan, MSU

Almost Mathematics
 Chuangtian Guan, MSU
 Almost Mathematics
 09/26/2019
 10:00 AM  12:00 PM
 C329 Wells Hall
No abstract available.

19608

Thursday 9/26 11:30 AM

Corey Jones, The Ohio State University

The higher dimensional algebra of matrix product operators and quantum spin chains
 Corey Jones, The Ohio State University
 The higher dimensional algebra of matrix product operators and quantum spin chains
 09/26/2019
 11:30 AM  12:30 PM
 C304 Wells Hall
In the context of 1D quantum spin chains, matrix product operators provide a way to study nonlocal operators such as translation in terms of quasilocal information. They have been used to describe a generalized form of symmetry for 1D systems on the boundary of 2D topological phases. In this talk, we will introduce some concepts of higher dimensional algebra, and a broad hypotheses about higher categories and spatially extended quantum systems. We will then explain how the collection of matrix product operators assembles into a higher (symmetric monoidal 2) category, and discuss some implications of this. Based on joint work with David Penneys.

19649

Thursday 9/26 1:00 PM

A. Volberg/P. Mozolyako

Unexpected combinatorial properties of all planar measures
 A. Volberg/P. Mozolyako
 Unexpected combinatorial properties of all planar measures
 09/26/2019
 1:00 PM  1:50 PM
 C517 Wells Hall
We will start with paraproductsoperators used in PDE to prove Leibniz rule with fractional derivatives. Then we move to biparameter paraproducts and prove the property from the title.

18580

Thursday 9/26 2:00 PM

David Boozer, UCLA

Holonomy perturbations of the ChernSimons functional for lens spaces
 David Boozer, UCLA
 Holonomy perturbations of the ChernSimons functional for lens spaces
 09/26/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
We describe a scheme for constructing generating sets for Kronheimer and Mrowka's singular instanton knot homology for the case of knots in lens spaces. The scheme involves Heegaardsplitting a lens space containing a knot into two solid tori. One solid torus contains a portion of the knot consisting of an unknotted arc, as well as holonomy perturbations of the ChernSimons functional used to define the homology theory. The other solid torus contains the remainder of the knot. The Heegaard splitting yields a pair of Lagrangians in the traceless $SU(2)$character variety of the twicepunctured torus, and the intersection points of these Lagrangians comprise the generating set that we seek. We illustrate the scheme by constructing generating sets for several example knots. Our scheme is a direct generalization of a scheme introduced by Hedden, Herald, and Kirk for describing generating sets for knots in $S^3$ in terms of Lagrangian intersections in the traceless $SU(2)$character variety for the 2sphere with four punctures.

19662

Monday 9/30 3:00 PM

Keshav Sutrave, MSU

Some kind of introduction to special relativity
 Keshav Sutrave, MSU
 Some kind of introduction to special relativity
 09/30/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
(Soft) The beginning of Einstein's theory of special relativity, which gives us a way of doing physics in different reference frames (observers in motion). Specifically: "What happens when you turn on a flashlight while already moving at half the speed of light?" I will introduce time dilation and length contraction, event simultaneity, and touch on the problem in electromagnetism, using many examples.

19612

Monday 9/30 4:30 PM

Joshua Ruiter, Michigan State

Root systems  a powerful tool for classification
 Joshua Ruiter, Michigan State
 Root systems  a powerful tool for classification
 09/30/2019
 4:30 PM  5:30 PM
 C304 Wells Hall
Root systems arose historically as a tool for classifying semisimple Lie algebras, but they can also be understood without that context. I will describe several concrete examples of root systems, with plenty of pictures. I will describe how to associate a special graph called a Dynkin diagram to a root system, and briefly describe the classification of root systems. If time allows, I will describe some of the applications to classifying semisimple Lie algebras and reductive algebraic groups. All you need to know to understand my talk is how to compute dot products on $\mathbb{R}^n$.

19663

Tuesday 10/1 12:00 PM

Keshav Sutrave, MSU

ChernSimons functional as a Morse function
 Keshav Sutrave, MSU
 ChernSimons functional as a Morse function
 10/01/2019
 12:00 PM  1:30 PM
 C117 Wells Hall
No abstract available.

19667

Tuesday 10/1 3:00 PM

Daping Weng, MSU

Double BottSamelson cell and the moduli space of microlocal rank1 sheaves
 Daping Weng, MSU
 Double BottSamelson cell and the moduli space of microlocal rank1 sheaves
 10/01/2019
 3:00 PM  4:00 PM
 C204A Wells Hall
Shende, Treumann, and Zaslow gave a combinatorial description of the moduli space of microlocal rank1 sheaves in their paper “Legendrian Knots and Constructible sheaves”. Following a result of Guillermou, Kashiwara, and Schapira, this moduli space is an invariant of Legendrian links. In this talk, I will review the definition and the cluster structure on the (undecorated) double BottSamelson cells, and show that in the cases of positive braids of Dynkin type A_r, the undecorated double BottSamelson cells are isomorphic to moduli spaces of microlocal rank1 sheaves associated to the corresponding braid closures. As a corollary, the undecorated double BottSamelson cells of Dynkin type A_r are also Legendrian link invariants for positive braid closures. If time allows, I will also talk about how to count F_q points on the undecorated double BottSamelson cells.

19646

Wednesday 10/2 3:00 PM

Victoria Hand , University of Colorado, Boulder; Elizabeth Mendoza, University of California, Irvine; Justin TenEyck, “I have a Dream” Foundation of Boulder County

Toward Rehumanizing Mathematics Education: Participatory Approaches to Noticing in Mathematics Classrooms
 Victoria Hand , University of Colorado, Boulder; Elizabeth Mendoza, University of California, Irvine; Justin TenEyck, “I have a Dream” Foundation of Boulder County
 Toward Rehumanizing Mathematics Education: Participatory Approaches to Noticing in Mathematics Classrooms
 10/02/2019
 3:00 PM  4:30 PM
 252 EH
Researchers are increasingly calling for participatory approaches to educational research that center the voices, experiences, and participation of minoritized communities. This talk will report on the CoAttend research project, which is grounded in a participatory approach to mathematics teacher noticing. The project involves mathematics teachers, leaders of local communitybased organizations and university researchers in collectively understanding expansive, multisensory noticing that supports rehumanizing practices in mathematics classrooms. All participants are positioned as researchers and coanalyze project data in video club meetings and summer institutes. We will describe emerging findings from the project, both in terms of the noticing framework, as well as the participatory process.

19664

Thursday 10/3 10:00 AM

Zhihao Zhao, MSU

Nonarchimedean Banach algebras vis commutative algebra
 Zhihao Zhao, MSU
 Nonarchimedean Banach algebras vis commutative algebra
 10/03/2019
 10:00 AM  12:00 PM
 C329 Wells Hall
No abstract available.

18586

Thursday 10/3 2:00 PM

Rita Gitik, Michigan

On Geodesic Triangles in the Hyperbolic Plane
 Rita Gitik, Michigan
 On Geodesic Triangles in the Hyperbolic Plane
 10/03/2019
 2:00 PM  2:50 PM
 C304 Wells Hall
Let M be an orientable hyperbolic surface without boundary and
let c be a closed geodesic in M. We prove that any side of any triangle formed by distinct lifts of c in the hyperbolic plane is shorter than c. The talk will be presented for advanced undergraduate and beginning graduate students.

19653

Monday 10/7 3:00 PM

Joe Melby, MSU

Complexity, 3Manifolds, and Zombies
 Joe Melby, MSU
 Complexity, 3Manifolds, and Zombies
 10/07/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
An important invariant of a pathconnected topological space X is the number of homomorphisms from the fundamental group of X to a finite, nonabelian, simple group G. Kuperberg and Samperton proved that, although these invariants can be powerful, they are often computationally intractable, particularly when X is an integral homology 3sphere. More specifically, they prove that the problem of counting such homomorphisms is #Pcomplete via a reduction from a known #Pcomplete circuit satisfiability problem. Their model constructs X from a wellchosen Heegaard surface and a mapping class in its Torelli group. We will introduce the basics of complexity for counting problems, summarize the reduction used by KS to bound the problem of counting homomorphisms, and discuss some of the topological and quantum computing implications of their results.

19671

Monday 10/7 4:30 PM

Zheng Xiao, MSU

Recent results of GCD problems on almost $S$units and recurrences
 Zheng Xiao, MSU
 Recent results of GCD problems on almost $S$units and recurrences
 10/07/2019
 4:30 PM  5:30 PM
 C517 Wells Hall
The GCD problem is one of the major problems in Diophantine Geometry. Corvaja, Zannier and Bugeaud first gave a fundamental result on GCD of integers powers and then generalized to rational numbers and algebraic numbers by many mathematicians. In this talk I will introduce recent GCD results on $S$units due to Levin and generalize to almost $S$units. I will give the definition of almost units and present the main theorem of GCD on multivariable polynomials, which is lead to a result about recurrence sequences. If time allows, I will also introduce Silverman’s generalized GCD along the blow up of a closed subscheme and apply to abelian surface case and its connection to Vojta’s conjecture.

19674

Tuesday 10/8 12:00 PM

Thomas Walpuski, MSU

A sketch of the construction of instanton Floer homology
 Thomas Walpuski, MSU
 A sketch of the construction of instanton Floer homology
 10/08/2019
 12:00 PM  1:30 PM
 C117 Wells Hall
No abstract available.

19679

Tuesday 10/8 3:00 PM

Daping Weng, MSU

Double BottSamelson cell and the moduli space of microlocal rank1 sheaves
 Daping Weng, MSU
 Double BottSamelson cell and the moduli space of microlocal rank1 sheaves
 10/08/2019
 3:00 PM  4:00 PM
 C204A Wells Hall
Shende, Treumann, and Zaslow gave a combinatorial description of the moduli space of microlocal rank1 sheaves in their paper “Legendrian Knots and Constructible sheaves”. Following a result of Guillermou, Kashiwara, and Schapira, this moduli space is an invariant of Legendrian links. In this talk, I will review the definition and the cluster structure on the (undecorated) double BottSamelson cells, and show that in the cases of positive braids of Dynkin type A_r, the undecorated double BottSamelson cells are isomorphic to moduli spaces of microlocal rank1 sheaves associated to the corresponding braid closures. As a corollary, the undecorated double BottSamelson cells of Dynkin type A_r are also Legendrian link invariants for positive braid closures. If time allows, I will also talk about how to count F_q points on the undecorated double BottSamelson cells.

19675

Wednesday 10/9 3:00 PM

Romyar Sharifi, UCLA

Cocycles valued in motivic cohomology
 Romyar Sharifi, UCLA
 Cocycles valued in motivic cohomology
 10/09/2019
 3:00 PM  4:00 PM
 C304 Wells Hall
I will describe joint work in progress with Akshay Venkatesh on the construction of 1cocycles on $\mathrm{GL}_2(\mathbb{Z})$ valued in a limit of second motivic cohomology groups of open subschemes of the square of (1) the multiplicative group over the rationals and (2) a universal elliptic curve. I’ll explain how these cocycles specialize to homomorphisms taking modular symbols to special elements in second cohomology groups of cyclotomic fields and modular curves in the respective cases.

19681

Thursday 10/10 11:30 AM

Jeffrey Schenker, Michigan State University

An ergodic theorem for homogeneously distributed quantum channels with applications to matrix product states
 Jeffrey Schenker, Michigan State University
 An ergodic theorem for homogeneously distributed quantum channels with applications to matrix product states
 10/10/2019
 11:30 AM  12:30 PM
 C304 Wells Hall
Quantum channels represent the most general physical evolution of a quantum system through unitary evolution and a measurement process. Mathematically, a quantum channel is a completely positive and trace preserving linear map on the space of $D\times D$ matrices. We consider ergodic sequences of channels, obtained by sampling channel valued maps along the trajectories of an ergodic dynamical system. The repeated composition of these maps along such a sequence could represent the result of repeated application of a given quantum channel subject to arbitrary correlated noise. It is physically natural to assume that such repeated compositions are eventually strictly positive, since this is true whenever any amount of decoherence is present in the quantum evolution. Under such an hypothesis, we obtain a general ergodic theorem showing that the composition of maps converges exponentially fast to a rankone  “entanglement breaking’’ – channel. We apply this result to describe the thermodynamic limit of ergodic matrix product states and prove that correlations of observables in such states decay exponentially in the bulk. (Joint work with Ramis Movassagh)

19670

Thursday 10/10 1:00 PM

Pavel Mozolyako, MSU

Embedding on bitree
 Pavel Mozolyako, MSU
 Embedding on bitree
 10/10/2019
 1:00 PM  1:50 PM
 C517 Wells Hall
No abstract available.

18597

Thursday 10/10 4:10 PM

Romyar Sharifi, UCLA

Modular symbols and the arithmetic of cyclotomic fields
 Romyar Sharifi, UCLA
 Modular symbols and the arithmetic of cyclotomic fields
 10/10/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
The arithmetic of cyclotomic fields, and the structure of their class groups, has been studied since the time of Kummer in connection with Fermat’s Last Theorem. The work of Ribet in 1976 uncovered a subtle influence of the geometry of modular curves on this structure. I’ll discuss how this connection goes even deeper and define a surprisingly explicit map from the homology group of a modular curve to a Kgroup related to the class group of a cyclotomic field. I’ll then indicate how this is turning out to be just one instance of a more general phenomenon, touching briefly on joint work with Takako Fukaya and Kazuya Kato and separate joint work with Akshay Venkatesh.

19633

Friday 10/11 4:10 PM

Arvind Krishna Saibaba, North Carolina State University

Randomized algorithms for lowrank tensor decompositions
 Arvind Krishna Saibaba, North Carolina State University
 Randomized algorithms for lowrank tensor decompositions
 10/11/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
Many applications in data science and scientific computing require the working with largescale datasets that are expensive to store and manipulate. These datasets have inherent multidimensional structure that can be exploited in order to efficiently compress and
store them in an appropriate tensor format. In recent years, randomized matrix methods have been used to efficiently and accurately compute lowrank matrix decompositions. Motivated by this success, we develop several randomized algorithms for compressing
tensor datasets in the Tucker format. We present probabilistic error analysis for our algorithms and numerical results on several datasets: synthetic test tensors, and realistic applications including the compression of facial image samples in the Olivetti database, and word counts in the Enron email dataset.
Joint work with Rachel Minster (NC State) and Misha Kilmer (Tufts)

19654

Monday 10/14 3:00 PM

Zhe Zhang, MSU

An introduction to intersection forms: Taking K3 surface as an example
 Zhe Zhang, MSU
 An introduction to intersection forms: Taking K3 surface as an example
 10/14/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
I’ll define intersection product both on 4 manifolds and in the algebraic geometry setting, then introduce the blow up technique and give some easy examples. After that I will jump to K3 surface, give definition and constructions, and talk a little bit about the elliptic fibrations of K3. If I still have time, I will talk about the relation between intersection form and characteristic classes.

19614

Monday 10/14 4:30 PM

Dan Normand, Harvard University

The Isomorphism Theorems in an Abelian Category
 Dan Normand, Harvard University
 The Isomorphism Theorems in an Abelian Category
 10/14/2019
 4:30 PM  5:30 PM
 C304 Wells Hall
It is often said that abelian categories are where homology can "naturally" occur. As the notion of an isomorphism is indispensable to the study of homologyand an innate aspect of a category, one would hope that there are analogues to the usual three isomorphism theorems of algebra in an arbitrary abelian category. In this [talk] we show that there are indeed such analogues, and we spend time developing the machinery to implement them

19680

Tuesday 10/15 12:00 PM

Wenchuan Tian, MSU

Linear analysis on cylindricalend manifolds
 Wenchuan Tian, MSU
 Linear analysis on cylindricalend manifolds
 10/15/2019
 12:00 PM  1:30 PM
 C117 Wells Hall
Donaldson Ch. 3

20682

Tuesday 10/15 1:05 PM

Leonid Chekhov, MSU

FenchelNielsen coordinates on Riemann surfaces and cluster algebras
 Leonid Chekhov, MSU
 FenchelNielsen coordinates on Riemann surfaces and cluster algebras
 10/15/2019
 1:05 PM  2:05 PM
 C304 Wells Hall
It is a 30(at least)year old subject: it is known since long that both the standard FenchelNIelsen (lengthstwists) coordinates and (Y)cluster coordinates (if we have holes) result in the same Goldman bracket on the set of geodesic functions on Riemann surfaces. The proof (of "local" nature in the first case and of "global" in the second) implies that these two sets of coordinates realise the same Poisson algebra. Nevertheless, constructing a direct transition between these two sets was elusive mainly due to complexity of the transition. For a sphere with 4 holes and torus with one hole, the corresponding formulas were obtained by Nekrasov, Rosly and Shatashvili in 2011. I present some preliminary results on the corresponding algebras in the general case and discuss possible relations to objects called YangYang functionals.

19677

Wednesday 10/16 3:00 PM

Aklilu Zeleke, MSU

New and Old Combinatorial Identities Part I
 Aklilu Zeleke, MSU
 New and Old Combinatorial Identities Part I
 10/16/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
Binomial coefficients $n \choose k$ appear in different areas of mathematics (in Pascal's triangle, counting problems and computing probabilities to name few). There are also many identities that involve binomial coefficients. In this talk we will discuss new and old identities that represent positive integers and in some cases real numbers. These identities are derived from studying the asymptotic behavior of the roots of a generalized Fibonacci polynomial sequence
given by $F_{j}(x)=x^{j}...x1$.

19632

Thursday 10/17 2:00 PM

Jesse Madnick , McMaster University

Bubble Tree Convergence of Parametrized Associative Submanifolds
 Jesse Madnick , McMaster University
 Bubble Tree Convergence of Parametrized Associative Submanifolds
 10/17/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
In symplectic geometry, part of Gromov's Compactness Theorem asserts that sequences of holomorphic curves with bounded energy have subsequences that converge to bubble trees, and that both energy and homotopy are preserved in this "bubble tree limit." In $G_2$ geometry, the analogues of holomorphic maps are the "associative Smith maps." In this talk, we'll see that familiar analytic features of holomorphic maps also hold for associative Smith maps. In particular, we'll describe how sequences of associative Smith maps give rise to bubble trees, and how energy and homotopy are again preserved in the limit. This is joint work with Da Rong Cheng and Spiro Karigiannis.

18588

Thursday 10/17 4:10 PM

Frank Sottile, Texas A&M University

Higher convexity for complements of tropical objects
 Frank Sottile, Texas A&M University
 Higher convexity for complements of tropical objects
 10/17/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
Gromov generalized the notion of convexity for open subsets
of $\mathbf{R}^n$ with hypersurface boundary, defining $k$convexity, or
higher convexity and Henriques applied the same notion to
complements of amoebas. He conjectured that the complement
of an amoeba of a variety of codimension $k+1$ is $k$convex.
I will discuss work with Mounir Nisse in which we study the
higher convexity of complements of coamoebas and of tropical
varieties, proving Henriques' conjecture for coamoebas and
establishing a form of Henriques' conjecture for tropical varieties in some cases.

19626

Friday 10/18 4:10 PM


The talk this week has been cancelled.

 The talk this week has been cancelled.
 10/18/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
The talk this week has been cancelled.

19683

Monday 10/21 12:00 PM

Jack Smith, MSU; Shiv Karunakaran, MSU

When the Game Changes: The Development of Student Agency and Autonomy in Challenging Undergraduate Mathematics
 Jack Smith, MSU; Shiv Karunakaran, MSU
 When the Game Changes: The Development of Student Agency and Autonomy in Challenging Undergraduate Mathematics
 10/21/2019
 12:00 PM  1:00 PM
 115 Erickson Hall
In their precollege and introductory collegiate mathematics coursework, students learn that mathematics centrally, if not exclusively involves computation. But many who pursue STEM disciplines routinely could encounter a quite different kind of mathematical work: The composition and evaluation of formal mathematical arguments, including proofs. The locus of this shift in mathematical activity on the MSU campus is MTH 299, Transitions, which introduces students to the basics of proof and argument. In the talk, we will present our current work conceptualizing agency and autonomy, the students who take the course, the challenges they face, and what we are learning about their experience in the course. We hope that these lessons will prove useful to all efforts to enrich introduction to proof mathematics courses.

19655

Monday 10/21 3:00 PM

Brandon Bavier, MSU

The Ends of Hyperbolic Manifolds
 Brandon Bavier, MSU
 The Ends of Hyperbolic Manifolds
 10/21/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
When studying knots, we can often get a lot of information by removing the knot from space, and looking at the knot complement. It's pretty natural to ask, then, what happens to the area close to the removed knot? We call these areas cusps, and, in the case of hyperbolic knots, the cusp alone can tell us quite a lot. In this talk, we will give an introduction to these cusps, including their uses in topology, as well as how to find invariants from them.

20683

Monday 10/21 4:10 PM

Andy Krause, MSU

Instructional Faculty Observations and Evaluation
 Andy Krause, MSU
 Instructional Faculty Observations and Evaluation
 10/21/2019
 4:10 PM  5:00 PM
 C109 Wells Hall
We'll revisit the Instructional Faculty observation structure (from our meeting in Spring) and organize classroom observations for the fall.

19629

Monday 10/21 4:30 PM

Yu Shen, Michigan State

Serre Duality I
 Yu Shen, Michigan State
 Serre Duality I
 10/21/2019
 4:30 PM  5:30 PM
 C304 Wells Hall
Serre duality was first proved by Serre in 1950s. It is a very useful tool in algebraic and complex geometry. In this lecture, I will use Čech cohomology to prove Serre duality of projective varieties. If time permits, I would like to talk about some applications of it.

20684

Tuesday 10/22 12:00 PM

Gorapada Bera, MSU

Linear analysis on cylindricalend manifolds (continued)
 Gorapada Bera, MSU
 Linear analysis on cylindricalend manifolds (continued)
 10/22/2019
 12:00 PM  1:30 PM
 C117 Wells Hall
No abstract available.

20686

Tuesday 10/22 3:00 PM

Leonid Chekhov, MSU

FenchelNielsen coordinates on Riemann surfaces and cluster algebras
 Leonid Chekhov, MSU
 FenchelNielsen coordinates on Riemann surfaces and cluster algebras
 10/22/2019
 3:00 PM  4:00 PM
 C204A Wells Hall
It is a 30(at least)year old subject: it is known since long that both the standard FenchelNIelsen (lengthstwists) coordinates and (Y)cluster coordinates (if we have holes) result in the same Goldman bracket on the set of geodesic functions on Riemann surfaces. The proof (of "local" nature in the first case and of "global" in the second) implies that these two sets of coordinates realise the same Poisson algebra. Nevertheless, constructing a direct transition between these two sets was elusive mainly due to complexity of the transition. For a sphere with 4 holes and torus with one hole, the corresponding formulas were obtained by Nekrasov, Rosly and Shatashvili in 2011. I present some preliminary results on the corresponding algebras in the general case and discuss possible relations to objects called YangYang functionals.

19676

Wednesday 10/23 3:00 PM

Sumit Chandra Mishra, Emory University

Localglobal principle for norms over semiglobal fields
 Sumit Chandra Mishra, Emory University
 Localglobal principle for norms over semiglobal fields
 10/23/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
Let $K$ be a complete discretely valued field with
residue field $\kappa$.
Let $F$ be a function field in one variable over $K$
and $\mathscr{X}$ a regular proper model of $F$
with reduced special fibre $X$ a union of regular curves
with normal crossings.
Suppose that the graph associated to
$\mathscr{X}$ is a tree (e.g. $F = K(t)$).
Let $L/F$ be a Galois extension of degree $n$ with Galois group $G$
and $n$ coprime to char$(\kappa)$.
Suppose that $\kappa$ is algebraically closed field or
a finite field containing a primitive $n^{\rm th}$ root of unity.
Then we show that an element in $F^*$ is a norm
from the extension $L/F$ if it is a norm from the
extensions $L\otimes_F F_\nu/F_\nu$
for all discrete valuations $\nu$ of $F$.

19638

Thursday 10/24 11:30 AM

Houssam AbdulRahman, U Arizona

Entanglement bounds in the XXZ spin chain
 Houssam AbdulRahman, U Arizona
 Entanglement bounds in the XXZ spin chain
 10/24/2019
 11:30 AM  12:30 PM
 C304 Wells Hall
We consider the XXZ chain in the Ising phase. The particle number conservation property is used to write the Hamiltonian in a hardcore particles formulation over the $N$symmetric product of graphs, where $N\in\mathbb{N}_0$ is the number of conserved particle. The droplet regime corresponds to a band at the bottom of the spectrum of the model consisting of a connected set (a droplet) of downspins, up to an exponential error. It is interesting to know that in the formulation over the $N$symmetric product graphs, with a fixed $N\geq 1$, the XXZ chain can be seen as a onedimensional model only when it is restricted to droplet states. This justifies the recent manybody localization indicators proved in the droplet regime by Elgart/Klein/Stolz and Beaud/Warzel for the disordered model, including an area law of arbitrary states in that localized phase. As a first step beyond the droplet regime, we show that the entanglement of arbitrary states above the droplet regime (associated with multiple droplets/clusters) does not follow area laws, and instead, it follows a logarithmically corrected (enhanced) area law. We will comment on the effects of disorder on entanglement, and show how our results hint a phase transition.
(joint work with C. Fischbacher and G. Stolz, arXiv1907.11420)

19641

Thursday 10/24 2:00 PM

Lev TovstopyatNelip, MSU

Obstructing Lagrangian link cobordisms via Heegaard Floer homology.
 Lev TovstopyatNelip, MSU
 Obstructing Lagrangian link cobordisms via Heegaard Floer homology.
 10/24/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
I'll explain how an invariant of Legendrian links in knot Floer homology can be used to obstruct the existence of decomposable Lagrangian link cobordisms in a very general setting. The argument involves braiding the ends of the cobordism about open books and appealing to an algebraic property of the Legendrian invariant called comultiplication. Much of the talk will be spent describing the topological and contact geometric ingredients.

18600

Thursday 10/24 4:10 PM

Robin Graham, University of Washington

Geodesic Xray Transforms and Boundary Rigidity
 Robin Graham, University of Washington
 Geodesic Xray Transforms and Boundary Rigidity
 10/24/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
This talk will introduce the problem of injectivity and
inversion of geodesic Xray transforms in various geometric settings. The
associated nonlinear boundary rigidity problem, which consists of
determining a Riemannian metric on a compact manifoldwithboundary from
the lengths of its geodesics joining boundary points, will also be
discussed. Classical results and recent progess will be described,
including current research on the analogous questions in the setting of
asymptotically hyperbolic manifolds.

19656

Monday 10/28 3:00 PM

Arman Tavakoli, MSU

Introduction to the YangMills equation
 Arman Tavakoli, MSU
 Introduction to the YangMills equation
 10/28/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
The YangMills equation is a celebrated topic that is studied in differential geometry and particle physics. We will motivate the equation as a generalization of Maxwell's equations, define the relevant geometrical objects and discuss their properties.

19673

Monday 10/28 4:00 PM

Olga Turanova, MSU

Partial differential equations from evolutionary ecology
 Olga Turanova, MSU
 Partial differential equations from evolutionary ecology
 10/28/2019
 4:00 PM  5:00 PM
 C304 Wells Hall
In collaboration with the AWM Student Chapter, we are most happy to welcome Professor Turanova to MSU! The abstract of her talk is:
I will describe the analysis of some PDEs that arise as models of ecological and evolutionary processes. There will be (some discussion of) poisonous toads!

19630

Monday 10/28 4:30 PM

Yu Shen, Michigan State

Serre Duality II
 Yu Shen, Michigan State
 Serre Duality II
 10/28/2019
 4:30 PM  5:30 PM
 C517 Wells Hall
Serre duality was first proved by Serre in 1950s. It is a very useful tool in algebraic and complex geometry. In this lecture, I will use Čech cohomology to prove Serre duality of projective varieties. If time permits, I would like to talk about some applications of it.

20685

Tuesday 10/29 12:00 PM

Gorapada Bera, MSU

Gauge theory and tubular ends
 Gorapada Bera, MSU
 Gauge theory and tubular ends
 10/29/2019
 12:00 PM  1:30 PM
 C117 Wells Hall
No abstract available.

20692

Tuesday 10/29 3:00 PM

Alexander Shapiro, UC Berkeley

Character varieties, Coulomb branches, and clusters.
 Alexander Shapiro, UC Berkeley
 Character varieties, Coulomb branches, and clusters.
 10/29/2019
 3:00 PM  4:00 PM
 C204A Wells Hall
Quantum groups admit two different geometric realizations: as quantized character varieties and as quantized Coulomb branches of certain gauge theories. These realizations endow a quantum group with two, a priori different, cluster structures. In this talk I will show these structures, explain why they coincide, and say what they have to do with GelfandTsetlin subalgebras, higher rank Fenchel–Nielsen coordinates, and modular functor from higher Teichmüller theory. This talk will be based on joint works with Gus Schrader.

19678

Wednesday 10/30 3:00 PM

Aklilu Zeleke, MSU

New and Old Combinatorial Identities Part II
 Aklilu Zeleke, MSU
 New and Old Combinatorial Identities Part II
 10/30/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
Using a probabilistic approach, we derive some interesting identities involving beta functions. These results generalize certain wellknown combinatorial identities involving binomial coefficients and gamma functions.

19619

Thursday 10/31 2:00 PM

Boyu Zhang, Princeton University

Classification of links with Khovanov homology of minimal rank
 Boyu Zhang, Princeton University
 Classification of links with Khovanov homology of minimal rank
 10/31/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
In this talk, I will present a classification of links whose Khovanov homology has minimal rank, which answers a question asked by Batson and Seed. The proof is based on an excision formula for singular instanton Floer homology that allows the excision surface to intersect the singularity. We will use the excision theorem to define an instanton Floer homology for tangles on sutured manifolds, and show that its gradings detect the generalized Thurston norm for punctured surfaces. This is joint work with Yi Xie.

18589

Thursday 10/31 4:10 PM

Robert Pego, Carnegie Mellon University

Dynamics in models of coagulation and fragmentation
 Robert Pego, Carnegie Mellon University
 Dynamics in models of coagulation and fragmentation
 10/31/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
Coaglationfragmentation equations are simple, nonlocal models for evolution of the size distribution of clusters, appearing widely in science and technology. But few general analytical results characterize their dynamics. Solutions can exhibit selfsimilar growth, singular mass transport, and weak or slow approach to equilibrium. I will review some recent results in this vein, discussing: the cutoff phenomenon (as in card shuffling) for BeckerDoering equilibration; stationary and spreading profiles in a datadriven model of fish school size; and temporal oscillations recently found in models lacking detailed balance. A special role is played by Bernstein transforms and complex function theory for Pick or Herglotz functions.

20694

Friday 11/1 1:00 PM

Victor Lie, Purdue University

A unified approach to three themes in harmonic analysis
 Victor Lie, Purdue University
 A unified approach to three themes in harmonic analysis
 11/01/2019
 1:00 PM  2:00 PM
 C304 Wells Hall
Linked Abstract

19657

Monday 11/4 3:00 PM

Gorapada Bera, MSU

Introduction to Riemannian Holonomy
 Gorapada Bera, MSU
 Introduction to Riemannian Holonomy
 11/04/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
The holonomy group of a Riemannian manifold exhibits various geometric structures compatible with the metric. In 1955, M.Berger classified all possible Riemannian holonomy groups. Studying all these are more than one semester subject. So, in this talk after a brief introduction we overview very basics of these holonomy groups.

19672

Monday 11/4 4:30 PM

Zheng Xiao, Michigan State

Arithmetic intersection theory and Arakelov's Hodge Index Theorem
 Zheng Xiao, Michigan State
 Arithmetic intersection theory and Arakelov's Hodge Index Theorem
 11/04/2019
 4:30 PM  5:30 PM
 C304 Wells Hall
The famous MordellWeil conjecture was first proved by Faltings in a classical way, then Vojta gave an alternative proof using arithmetic Arakelov geometry, which is one big motivation for developing Arakelov theory into a mature tool. In this talk I will introduce Neron functions and divisors, which is an arithmetic approach to define divisors rather than classical algebraic geometry. We shall also cover arithmetic chow groups and the arithmetic intersection number. In the end I will present Neron symbols and use it to give a sketch proof of Arakelov’s Hodge Index Theorem.

20696

Tuesday 11/5 12:00 PM

Alex Waldron, MSU

Instanton homology of Seifertfibered homology 3spheres
 Alex Waldron, MSU
 Instanton homology of Seifertfibered homology 3spheres
 11/05/2019
 12:00 PM  1:30 PM
 C117 Wells Hall
Fintushel & Stern, 1990

20689

Tuesday 11/5 3:00 PM

Carl WangErickson, University of Pittsburg

Biordinary modular forms
 Carl WangErickson, University of Pittsburg
 Biordinary modular forms
 11/05/2019
 3:00 PM  4:00 PM
 C304 Wells Hall
It is known that pordinary cuspidal Hecke eigenforms give rise to 2dimensional global Galois representations which become reducible after restriction to a decomposition group at p. For which such forms is this restriction not only reducible but also splittable? Complex multiplication (CM) forms satisfy this plocal property, but is such a restrictive global property as CM necessary? In classical weights at least 2, it is expected that this is the case. We present a construction of "biordinary" padic modular forms, which can measure exceptions to this expectation. We also give evidence that there are nonCM but plocally splittable forms in padic weights. This is joint work with Francesc Castella.

19648

Tuesday 11/5 3:00 PM

Dan Rutherford, Ball State University

Normal rulings and augmentation varieties
 Dan Rutherford, Ball State University
 Normal rulings and augmentation varieties
 11/05/2019
 3:00 PM  4:00 PM
 C204A Wells Hall
Normal rulings are combinatorial structures associated to the front diagrams of 1dimensional Legendrian knots in R^3. They were introduced independently by Fuchs and ChekanovPushkar in the context of augmentations of the Legendrian DGalgebra and generating families. In this talk I will present joint work with B. Henry in which we construct a decomposition of the augmentation variety into disjoint pieces indexed by normal rulings. The pieces of the decomposition are products of algebraic tori and affine spaces with dimensions determined by the combinatorics of the ruling. As a consequence, the ruling polynomial invariants of ChekanovPushkar are seen to be equivalent to augmentation number invariants defined by counting augmentations to finite fields. The construction of the decomposition is based on considering Morse complex sequences which are combinatorial analogs of generating families.

20695

Wednesday 11/6 3:00 PM

Robert Bell, MSU

Variations of cops and robbers on infinite graphs
 Robert Bell, MSU
 Variations of cops and robbers on infinite graphs
 11/06/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
The game of cops and robbers is a two player pursuit and evasion game played on a discrete graph G. We study a variation of the classical rules which leads to a different invariant when G is an infinite graph. In this variation, called "weak cops and robbers," the cops win by preventing the robber from visiting any vertex infinitely often. In the classical game, if G is connected and planar, then the cops can always win if there are at least three cops. We prove that this is true in the weak game if G is a locally finite plane graph with no vertex accumulation points.

19645

Wednesday 11/6 4:10 PM

Ioakeim Ampatzoglou, University of Texas, Austin

Derivation of a ternary Boltzmann system
 Ioakeim Ampatzoglou, University of Texas, Austin
 Derivation of a ternary Boltzmann system
 11/06/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
In this talk work we present a rigorous derivation of a new kinetic equation describing the limiting behavior of a classical system of particles with three particle instantaneous interactions, which are modeled using
a nonsymmetric version of a ternary distance. The equation, which we call ternary Boltzmann equation, can be understood as a step towards modeling a dense gas in nonequilibrium. This is a joint work with Natasa Pavlović.

20698

Thursday 11/7 11:00 AM

Marios Velivasakis, University of Western Ontario

Schubert Varieties in Partial Flag Manifolds and Generalized SeveriBrauer Varieties
 Marios Velivasakis, University of Western Ontario
 Schubert Varieties in Partial Flag Manifolds and Generalized SeveriBrauer Varieties
 11/07/2019
 11:00 AM  12:00 PM
 C329 Wells Hall
Schubert varieties form one of the most important classes of singular algebraic varieties. They are also a kind of moduli spaces. One problem is that these varieties are not easy to understand and manipulate using only their geometric nature. In this talk, we will discuss about Schubert varieties and present a way to characterize them combinatorially. In addition, we will discuss how they relate to SeveriBrauer varieties SB(d,A) and how we can use their combinatorial description to answer questions about subvarieties of SB(d,A)

19639

Thursday 11/7 11:30 AM

Charles Smart, U Chicago

Localization for the AndersonBernoulli model on the integer lattice
 Charles Smart, U Chicago
 Localization for the AndersonBernoulli model on the integer lattice
 11/07/2019
 11:30 AM  12:30 PM
 C304 Wells Hall
Abstract: I will give a brief mathematical introduction to Anderson localization followed by a discussion of my recent work with Jian Ding. In our work we establish localization near the edge for the Anderson Bernoulli model on the two dimensional lattice. Our proof follows the program of BourgainKenig and uses a new unique continuation result inspired by BuhovskyLogunovMalinnikovaSodin. I will also discuss recent work of by Li and Zhang on the three dimensional case.

19643

Friday 11/8 4:10 PM

Kritika Singhal, Ohio State University

Sketching and Clustering Metric Measure Spaces
 Kritika Singhal, Ohio State University
 Sketching and Clustering Metric Measure Spaces
 11/08/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
Two important optimization problems in the analysis of geometric data sets are clustering and simplification (sketching) of data. Clustering refers to partitioning a dataset, according to some rule, into sets of smaller size with the aim of extracting important information from the data. Sketching, or simplification of data, refers to approximating the input data with another dataset of much smaller size in such a way that properties of the input dataset are retained by the smaller dataset. In this sense, sketching facilitates understanding of the data.
There are many clustering methods for metric spaces (mm spaces) already present in literature, such as kcenter clustering, kmedian clustering, kmeans clustering, etc. A natural method for obtaining a ksketch of a metric space (mm space) is by viewing the space of all metric spaces (mm space) as a metric under GromovHausdorff (GromovWasserstein) distance, and then determining, under this distance, the k point metric space (mm space) closest to the input metric space (mm space).
These two problems of sketching and clustering, a priori, look completely unrelated. However, we establish a duality i.e. an equivalence between these notions of sketching and clustering. For metric spaces, we consider the case where the clustering objective is minimizing the maximum cluster diameter. We show that the ratio between the sketching and clustering objectives is constant over compact metric spaces.
We extend these results to the setting of metric measure spaces where we prove that the ratio of sketching to clustering objectives is bounded both above and below by some universal constants. In this setting, the clustering objective involves minimizing various notions of the $\ell_p$diameters of the clusters.
We also identify procedures/maps that transform a solution of the sketching problem to a solution of the clustering problem, and viceversa. These maps give rise to algorithms for performing these transformations and, by virtue of these algorithms, we are able to obtain an approximation to the ksketch of a metric measure space (metric space) using known approximation algorithms for the respective clustering objectives. This is joint work with Facundo Memoli and Anastasios Sidiropoulos, and is available online at https://arxiv.org/abs/1801.00551.

20702

Monday 11/11 12:00 PM

Betty Phillips, MSU; AJ Edson, MSU

Embedding the CMP Curriculum into a Digital Collaborative Platform
 Betty Phillips, MSU; AJ Edson, MSU
 Embedding the CMP Curriculum into a Digital Collaborative Platform
 11/11/2019
 12:00 PM  1:00 PM
 115 Erickson Hall
The context for the work is transitioning the Connected Mathematics, an established
problembased curriculum, to a digital environment. In CMP, mathematical understandings are embedded in tasks which are carefully sequenced to build deep understanding of important mathematical ideas. In this session, we report on curriculum research and development efforts to leverage digital technologies to support student collaboration and enhance students’ productive disciplinary engagement in mathematics. Bring a laptop to partake in the collaborative environment.

19658

Monday 11/11 3:00 PM

Wenchuan Tian, MSU

Properties of Busemann function on manifolds with nonnegative sectional curvature outside of a compact set
 Wenchuan Tian, MSU
 Properties of Busemann function on manifolds with nonnegative sectional curvature outside of a compact set
 11/11/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
Busemann functions are useful. Cheeger and Gromoll used them to prove the splitting theorem for manifolds with nonnegative ricci curvature that contains a line. Yau used them to prove that complete noncompact manifolds with nonnegative Ricci curvature have at least linear volume growth.
In a paper called "Positive Harmonic Functions on Complete Manifolds with NonNegative Curvature Outside a Compact Set" Peter Li and LuenFai Tam also used Busemann function to show the existence of positive harmonic functions. I will talk about Li and Tam's proof of properties of Busemann function. The proof only uses Toponogov theorem and cosine law. The results of the proof is useful for the subsequent analysis part of the paper.

20699

Monday 11/11 4:30 PM

Joshua Ruiter, Michigan State

Field norm for algebraic groups, with a view towards nonsplit tori
 Joshua Ruiter, Michigan State
 Field norm for algebraic groups, with a view towards nonsplit tori
 11/11/2019
 4:30 PM  5:30 PM
 C304 Wells Hall
Field norm maps are useful in many areas of algebra, such as Galois theory. Using the language of (affine) algebraic groups, I will place the field norm in a larger context, as a particular instance of a certain natural transformation. This will set us up for my talk the following week, on special subgroups of algebraic groups called tori, and what it means for such tori to be split or nonsplit. In particular, the generalized norm will provide a (somewhat) concrete example of a nonsplit torus.

20704

Tuesday 11/12 12:00 PM

Lev Tovstopyat, MSU

On the surgery exact triangle in Heegaard Floer homology
 Lev Tovstopyat, MSU
 On the surgery exact triangle in Heegaard Floer homology
 11/12/2019
 12:00 PM  1:30 PM
 C117 Wells Hall
No abstract available.

20706

Wednesday 11/13 3:00 PM

Robert Bell, MSU

Cop number and edge deletion, addition, or subdivision
 Robert Bell, MSU
 Cop number and edge deletion, addition, or subdivision
 11/13/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
We present new and old results about the effect of edge operations on the cop number of a finite graph.
This project was part of the SURIEM summer REU program in 2019 at MSU.

20703

Wednesday 11/13 4:10 PM

Farhan Abedin, Michigan State University

Regularity results for a class of KolmogorovFokkerPlanck equations in nondivergence form
 Farhan Abedin, Michigan State University
 Regularity results for a class of KolmogorovFokkerPlanck equations in nondivergence form
 11/13/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
The KolmogorovFokkerPlanck equation is a degenerate parabolic equation arising in models of gas dynamics from kinetic theory. The operator is of the form
$$\mathcal{L}_Au := \mathrm{tr}(A(v,y,t) D^2_v u) + v \cdot \nabla_yu  \partial_tu,$$ where $$u(v,y,t): \mathbb{R}^{2d+1} \to \mathbb{R} \text{ and } 0 < \lambda \mathbb{I}_d \leq A \leq \Lambda \mathbb{I}_d.$$
It is an open problem if nonnegative solutions of $\mathcal{L}_A u = 0$ in $\mathbb{R}^{2d+1}$ satisfy a scaleinvariant Harnack inequality, assuming the matrix coefficient $A$ is merely bounded and measurable. I will discuss recent joint work with Giulio Tralli in which progress is made on partially solving this problem.

20711

Thursday 11/14 3:00 PM

Dapeng Zhan, MSU

Timereversal of multipleforcepoint SLE$_\kappa(\underline\rho)$ with all force points lying on the same side
 Dapeng Zhan, MSU
 Timereversal of multipleforcepoint SLE$_\kappa(\underline\rho)$ with all force points lying on the same side
 11/14/2019
 3:00 PM  3:50 PM
 C506 Wells Hall
We define intermediate SLE$_\kappa(\underline \rho)$ and reversed intermediate SLE$_\kappa(\underline\rho)$ processes using AppellLauricella multiple hypergeometric functions, and use them to describe the timereversal of multipleforcepoint chordal SLE$_\kappa(\underline \rho)$ curves in the case that all force points are on the boundary and lie on the same side of the initial point, and $\kappa $ and $\underline \rho=(\rho_1,\dots,\rho_m)$ satisfy that either $\kappa\in(0,4]$ and $\sum_{j=1}^k \rho_j>2$ for all $1\le k\le m$, or $\kappa\in(4,8)$ and $\sum_{j=1}^k \rho_j\ge \frac{\kappa}{2}2$ for all $1\le k\le m$.

20707

Thursday 11/14 4:00 PM

Jihye Hwang, Michigan State University

What do you mean by "show"? Is it the same as "prove"?
 Jihye Hwang, Michigan State University
 What do you mean by "show"? Is it the same as "prove"?
 11/14/2019
 4:00 PM  5:00 PM
 C304 Wells Hall
Students face a mathematical task whenever they involve in doing mathematics. We wondered whether the word used in posing question impact students’ response and we hypothesize that task provider’s intention and students’ response can be different. This talk focus on students interpretation of the different prompts, such as “prove,” “show,” “explain,” and “convince a classmate,” for proving tasks. This talk focuses on the two prompts, “prove” and “show” as the prompts are regarded as synonymous by many people, especially mathematicians. Although there exist similarities between the prompts, the result mainly demonstrates students possibly have different meaning for “prove” and “show” depending on individual and one possible relationship between the two prompts.

19618

Friday 11/15 10:30 AM

Marius Lemm, Harvard

Spectral gaps without frustration
 Marius Lemm, Harvard
 Spectral gaps without frustration
 11/15/2019
 10:30 AM  11:30 AM
 C304 Wells Hall
In quantum spin systems, the existence of a spectral gap above the ground state has strong implications for the lowenergy physics. We survey recent results establishing spectral gaps in various frustrationfree spin systems by verifying finitesize criteria. The talk is based on collaborations with AbdulRahman, Lucia, Mozgunov, Nachtergaele, Sandvik, Yang, Young, and Wang.

19640

Friday 11/15 4:10 PM

Yao Yao, Georgia Tech

Uniqueness and nonuniqueness of steady states of aggregationdiffusion equation
 Yao Yao, Georgia Tech
 Uniqueness and nonuniqueness of steady states of aggregationdiffusion equation
 11/15/2019
 4:10 PM  5:00 PM
 C304 Wells Hall
In this talk, I will discuss a nonlocal aggregation equation with degenerate diffusion, which describes the meanfield limit of interacting particles driven by nonlocal interactions and localized repulsion. When the interaction potential is attractive, it is previously known that all steady states must be radially decreasing up to a translation, but uniqueness (for a given mass) within this class was open, except for some special interaction potentials. For general attractive potentials, we show that the uniqueness/nonuniqueness criteria are determined by the power of the degenerate diffusion, with the critical power being m=2. Namely, for m>=2, we show the steady state for any given mass is unique for any attractive potential, by tracking the associated energy functional along a novel interpolation curve. And for 1<m<2, we construct examples of smooth attractive potentials, such that there are infinitely many radially decreasing steady states of the same mass. This is a joint work with Matias Delgadino and Xukai Yan.

19659

Monday 11/18 3:00 PM

Sarah Klanderman, MSU

Computations in Topological CoHochschild Homology
 Sarah Klanderman, MSU
 Computations in Topological CoHochschild Homology
 11/18/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
Hochschild homology (HH) is a classical algebraic invariant of rings that can be extended topologically to be an invariant of ring spectra, called topological Hochschild homology (THH). There exists a dual theory for coalgebras called coHochschild homology (coHH), and in recent work Hess and Shipley defined an invariant of coalgebra spectra called topological coHochschild homology (coTHH). In this talk we will discuss coTHH calculations and the tools needed to do them.

20700

Monday 11/18 4:30 PM

Joshua Ruiter, Michigan State

Split and nonsplit tori
 Joshua Ruiter, Michigan State
 Split and nonsplit tori
 11/18/2019
 4:30 PM  5:30 PM
 C517 Wells Hall
Tori are an important structural aspect of algebraic groups, and "split" vs "nonsplit" tori are especially important. Unfortunately, "nonsplit" phenomena only occur over nonalgebraically closed fields, so not all the traditional tools of classical algebraic geometry apply. Using the generalized field norm map from my talk last week, I'll describe a concrete example of a nonsplit torus. Then we'll try to use that example to try and understand the importance of nonsplit tori.

20717

Tuesday 11/19 11:30 AM

Brent Nelson, MSU

Derivations on von Neumann algebras
 Brent Nelson, MSU
 Derivations on von Neumann algebras
 11/19/2019
 11:30 AM  12:30 PM
 C304 Wells Hall
In this learning seminar style talk, I will define the notion of a derivation on a von Neumann algebra. I will also discuss their history and how they factor into modern research in operator algebras.

20710

Tuesday 11/19 12:00 PM

Matthew Hedden, MSU

Spectral sequence from Khovanov to instanton homology
 Matthew Hedden, MSU
 Spectral sequence from Khovanov to instanton homology
 11/19/2019
 12:00 PM  1:30 PM
 C117 Wells Hall
No abstract available.

20708

Tuesday 11/19 3:00 PM

Honghao Gao, MSU

Applications of augmentations in contact topology
 Honghao Gao, MSU
 Applications of augmentations in contact topology
 11/19/2019
 3:00 PM  4:00 PM
 C204A Wells Hall
Chekanov introduced a differential graded algebra as an invariant for Legendrian knots in standard contact manifold R^3. An augmentation is a rank 1 representation of the dga. Augmentations are accessible invariants, and the moduli space of augmentations carries important properties from both algebraic and geometric perspectives. In this talk, I will review some problems in contact topology and discuss the applications of augmentations.

20712

Tuesday 11/19 3:50 PM

Andrey Gogolyev, Ohio State University

Rigidity for higher dimensional expanding maps
 Andrey Gogolyev, Ohio State University
 Rigidity for higher dimensional expanding maps
 11/19/2019
 3:50 PM  4:50 PM
 C304 Wells Hall
Expanding maps are self covers of smooth compact manifolds which expand the lengths of all nonzero tangent vectors. Classification of such maps up to topological conjugacy is known due to work of Shub, Franks and Gromov. Classification up to smooth conjugacy should be quite different because periodic points of expanding maps carry invariants of $C^1$ conjugacy. Shub and Sullivan classified expanding maps on the circle up to smooth conjugacy on the circle. I will explain smooth classification of expanding maps in higher dimensions on and open dense set in the space of expanding maps. Joint work with F. Rodriguez Hertz.

20709

Wednesday 11/20 3:00 PM

Patrick Allen, UIUC

On the modularity of elliptic curves over imaginary quadratic fields
 Patrick Allen, UIUC
 On the modularity of elliptic curves over imaginary quadratic fields
 11/20/2019
 3:00 PM  4:00 PM
 C304 Wells Hall
The LanglandsTunnell theorem is an important starting point in Wiles's proof of the modularity of semistable elliptic curves over the rationals. Over imaginary quadratic fields it is unclear how to similarly use the LanglandsTunnell theorem and Wiles's strategy runs into problems right from the start. I will motivate and explain the subtle but fundamental issues that arise, and indicate how they can be circumvented in many cases. As an application, we deduce that a positive proportion of elliptic curves over imaginary quadratic fields are modular. This is joint work with Chandrashekhar Khare and Jack Thorne.

20690

Wednesday 11/20 3:30 PM

Michelle Cirillo, University of Delaware; Jennifer Reed, Odyssey Charter Middle School, Delaware

Learning Together Through Collaborative Research: The Case of Proof in Secondary Mathematics
 Michelle Cirillo, University of Delaware; Jennifer Reed, Odyssey Charter Middle School, Delaware
 Learning Together Through Collaborative Research: The Case of Proof in Secondary Mathematics
 11/20/2019
 3:30 PM  5:00 PM
 252 EH
The Proof in Secondary Classrooms (PISC) project is a design and development research study focused on secondary students’ success with mathematical proof. The goal of this project was to develop a new and improved intervention to support the teaching and learning of proof. The central research objective of this project was to develop a pedagogical framework and a corresponding set of lesson plans and support materials to guide teachers toward improving students’ success with proof. The primary educational objective of this project was to support mathematics educators in understanding particular subgoals of proof and developing strategies for teaching them. We present data and findings from our threeyear collaboration on this project (20162019), which made use of ideas from design research and lesson study, and we discuss lessons learned through our collaboration.

19609

Thursday 11/21 11:30 AM

Kari Eifler, Texas A&M University

The graph isomorphism game for quantum graphs
 Kari Eifler, Texas A&M University
 The graph isomorphism game for quantum graphs
 11/21/2019
 11:30 AM  12:30 PM
 C304 Wells Hall
Nonlocal games give us a way of observing quantum behaviour through the observation of only classical data. The graph isomorphism game is one such nonlocal game played by Alice and Bob which involves two finite, undirected graphs. A winning strategy for the game is called quantum if it utilizes some shared resource of quantum entanglement between the players. We say two graphs are quantum isomorphic if there is a winning quantum strategy for the graph isomorphism game. We show that the *algebraic, C*algebraic, and quantum commuting (qc) notions of a quantum isomorphism between classical graphs X and Y are all equivalent. This is based on joint work with M. Brannan, A. Chirvasitu, S. Harris, V. Paulsen, X. Su, and M. Wasilewski.

20714

Thursday 11/21 1:00 PM

Leonardo Abbrescia, MSU

Stability of traveling planewave solutions to Lorentzian vanishing mean curvature flow
 Leonardo Abbrescia, MSU
 Stability of traveling planewave solutions to Lorentzian vanishing mean curvature flow
 11/21/2019
 1:00 PM  1:50 PM
 C517 Wells Hall
Lorentzian minimal submanifolds of Minkowski space are the dynamic analogue of minimal surfaces in the elliptic regime. They are defined by the vanishing of mean curvature, which can be expressed as a system of geometric PDEs. With the requirement that the submanifold be Lorentzian, that is, that the induced metric is Lorentzian, the equations have a hyperbolic nature. Consequently, the natural approach to study them is via the Cauchy initial value problem. In this talk we discuss stability properties of traveling planewave solutions to these equations, and highlight the difficulties introduced by the "infinite energy" planewave background. This is joint work with Willie Wong.

19628

Thursday 11/21 2:00 PM

Akram Alishahi, University of Georgia

Braid invariant relating knot Floer homology and Khovanov homology
 Akram Alishahi, University of Georgia
 Braid invariant relating knot Floer homology and Khovanov homology
 11/21/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
Khovanov homology and knot Floer homology are two knot invariants that were defined around the same time, and despite their different constructions, share many formal similarities. After reviewing the construction of Khovanov homology and some of these similarities, we will discuss an algebraic braid invariant which is closely related to both Khovanov homology and the refinement of knot Floer homology into tangle invariants. This is a joint work with Nathan Dowlin.

21717

Thursday 11/21 4:00 PM

Craig Gross, Rachel Domagalski, MSU

Git/Github and Zotero Workshop
 Craig Gross, Rachel Domagalski, MSU
 Git/Github and Zotero Workshop
 11/21/2019
 4:00 PM  5:00 PM
 C204 Wells Hall
The AMS Grad Student Chapter is putting on a Git, GitHub, and Zotero workshop. If you want to know more about version control / staying organized / making .bib files / best collaboration practices, this workshop is for you! Please bring your laptop. Snacks will be provided!

20705

Friday 11/22 3:30 PM

Exchange Program and MSU Student Research Teams

Undergraduate MTH and STT Research Project Presentations
 Exchange Program and MSU Student Research Teams
 Undergraduate MTH and STT Research Project Presentations
 11/22/2019
 3:30 PM  7:00 PM
 C304 Wells Hall
Special event: Undergraduate MTH and STT Research Project Presentations
Exchange Program and MSU Student Research Teams will present the results of their research projects

19669

Friday 11/22 4:10 PM

Yeonhyang Kim, Central Michigan University

Qball imaging using predicted diffusion gradient directions
 Yeonhyang Kim, Central Michigan University
 Qball imaging using predicted diffusion gradient directions
 11/22/2019
 4:10 PM  5:00 PM
 A203 Wells Hall
We review the theory of qball imaging and describe a simple linear matrix formulation for the qball reconstruction based on spherical harmonic basis function interpolation. In this talk, we present a novel method to improve the qball reconstruction by determining appropriate positions at which a synthesized signal is obtained by combining surrounding signals in given diffusion gradient directions.

19660

Monday 11/25 3:00 PM

Hitesh Gakhar, MSU

TBD
 Hitesh Gakhar, MSU
 TBD
 11/25/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
TBD

20716

Tuesday 11/26 3:50 PM

Boris, Kalinin, Penn State University

Local rigidity for partially hyperbolic toral automorphisms
 Boris, Kalinin, Penn State University
 Local rigidity for partially hyperbolic toral automorphisms
 11/26/2019
 3:50 PM  4:50 PM
 C304 Wells Hall
We study perturbations of an irreducible ergodic toral automorphism $L$ with nontrivial center. For a small perturbation $f$ of $L$ with smooth center foliation we obtain results on regularity of the leaf conjugacy to $L$ and of a Holder topological conjugacy to $L$, when it exists. As a corollary, we show that for any symplectic perturbation a Holder conjugacy to $L$ must be smooth. For a totally irreducible $L$ with twodimensional center, we establish various equivalent conditions that ensure smooth conjugacy between $L$ and $f$. This is joint work with Andrey Gogolev and Victoria Sadovskaya

20715

Monday 12/2 10:00 AM

Meihua Tu, Medicine Design, Pfizer Inc.

The role of water molecules in Ketohexokinase (KHK) inhibitor design
 Meihua Tu, Medicine Design, Pfizer Inc.
 The role of water molecules in Ketohexokinase (KHK) inhibitor design
 12/02/2019
 10:00 AM  11:00 AM
 C304 Wells Hall
Increased fructose consumption and its subsequent metabolism have been implicated in hepatic steatosis, dyslipidemia, obesity, and insulin resistance in humans. Since ketohexokinase (KHK) is the principal enzyme responsible for fructose metabolism, inhibition of KHK may ameliorate nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) by decreasing fructose conversion to fructose1phosphate. Initial low MW hits were identified by fragment screening. A combination of parallel synthesis and structurebased drug design yielded a clinic candidate, currently in clinic trials. This presentation will focus on computational techniques that have been applied in the optimization of lead compounds. In particular, how water molecule energy profile in the binding pocket was used to guide compound design. Our successful fragmenttocandidate story will demonstrate the power of combining structurebased drug design with parallel chem.

19661

Monday 12/2 3:00 PM

Sanjay Kumar, MSU

TBD
 Sanjay Kumar, MSU
 TBD
 12/02/2019
 3:00 PM  3:50 PM
 C304 Wells Hall
TBD

19621

Thursday 12/5 2:00 PM

Shelly Harvey, Rice

Pure braids and link concordance
 Shelly Harvey, Rice
 Pure braids and link concordance
 12/05/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
If one considers the set of mcomponent based links in R^3
with a 4dimensional equivalence relationship on it, called
concordance, one can form a group called the link concordance group,
C^m. Questions in concordance are important in for classification
questions in topological and smooth 4manifolds It is well known that
the link concordance group contains the isotopy class of pure braid
with m strands, P_m. That is, two braids are concordant if and only
if they are isotopic! In the late 90's Tim Cochran, Kent Orr, and
Peter Teichner defined a filtration of the knot/link concordance group
called the nsolvable filtration. This filtration gives a way to
approximate whether a link is trivial in the group. We discuss the
relationship between pure braids and the nsolvable filtration as well
as various other more geometrically defined filtrations coming from
gropes and Whitney towers. This is joint work with Aru Ray and Jung
Hwan Park.

19668

Friday 12/6 4:10 PM

Neel Patel, University of Michigan

TBA
 Neel Patel, University of Michigan
 TBA
 12/06/2019
 4:10 PM  5:00 PM
 A203 Wells Hall
No abstract available.

20691

Tuesday 12/10 11:00 AM

Luca Di Cerbo, University of Florida

Price Inequalities and BenjaminiSchramm Convergence
 Luca Di Cerbo, University of Florida
 Price Inequalities and BenjaminiSchramm Convergence
 12/10/2019
 11:00 AM  12:00 PM
 C304 Wells Hall
In this talk, I will present a study of Betti numbers of sequences of compact negatively curved Riemannian manifolds BenjaminiSchramm converging to their universal covers. The main tools are a Price inequality for harmonic forms on negatively curved spaces, and an effective thickthin decomposition.
