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Applied Mathematics
 Zhaoran Wang, Northwestern University
 1WMINDS talk (passcode is the first prime number > 100).
 12/01/2022
 2:30 PM  3:30 PM
 Online (virtual meeting)
 Mark A Iwen ()
See https://sites.google.com/view/mindsseminar/home
Student Number Theory
 Peikai Qi, MSU
 Classic modular symbol over complex field
 12/01/2022
 3:00 PM  4:00 PM
 C204A Wells Hall
 Peikai Qi (qipeikai@msu.edu)
We will move from the classic modular symbol form to modular symbol over complex field. And we will use a lot of theorem from previous chapter as black box.

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Special Colloquium
 Our undergraduate research teams!
 Exchange Program REU Final Presentations
 12/02/2022
 6:30 PM  9:45 PM
 C304 Wells Hall
(Virtual Meeting Link)
 Jeanne Wald (wald@msu.edu)
Linked Abstract
Exchange Program REU Final Presentations
Speakers: Our undergraduate research teams!
Title: See the program, which includes descriptions of the research projects
Date: Friday December 2, 2022
Time: 6:30 p.m. – 9:45 p.m.
https://msu.zoom.us/j/92801969144
Meeting ID: 928 0196 9144
Passcode: 112358

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Operator Algebras Reading
 Alberto Takase, MSU
 The Integrated Density of States and the Gap Labeling Theorem via "KTheory"
 12/05/2022
 4:00 PM  5:30 PM
 C517 Wells Hall
 Brent Nelson (banelson@msu.edu)
My talk will be about the Integrated Density of States and the Gap Labeling Theorem via "KTheory". The primary source is Bellissard, Jean; Bovier, Anton; Ghez, JeanMichel \textit{Gap labelling theorems for onedimensional discrete Schrödinger operators}. Rev. Math. Phys. 4 (1992), no. 1, 1–37.

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Mathematical Physics and Operator Algebras
 Ekaterina Shchetka, University of Michigan
 Semiclassical analysis and spectrum of Harper operator
 12/06/2022
 11:00 AM  12:00 PM
 C304 Wells Hall
 Ilya Kachkovskiy (ikachkov@msu.edu)
In this talk we’ll discuss semiclassical analysis of difference operators in the complex plane via complex WKB method. As application the method can be used to study the spectrum of Harper operator (a.k.a. almost Mathieu operator, or Hofstadter model).
Dynamical Systems
 Yuping Ruan, University of Michigan
 Boundary rigidity and filling minimality via the barycenter method
 12/06/2022
 2:00 PM  3:00 PM
 A106 Wells Hall
 Fan Yang (yangfa31@msu.edu)
A compact manifold with a smooth boundary is boundary rigid if its boundary and boundary distance function uniquely determine its interior up to boundary preserving isometries. Under certain natural conditions, the notion of boundary rigidity is closely related to Gromov's filling minimality. In this talk, we will first give a brief overview of BuragoIvanov's approach to prove filling minimality and boundary rigidity for almost Euclidean and almost real hyperbolic metrics. Then we will explain how we generalize their results to regions in a rank1 symmetric space equipped with an almost symmetric metric. We will also explain the relations to BessonCourtoisGallot's barycenter constructions used in their celebrated volume entropy rigidity theorem.
Geometry and Topology
 Cameron Gates Rudd, Max Planck Institute, Bonn
 Untriangulating knots
 12/06/2022
 3:00 PM  4:00 PM
 Online (virtual meeting)
(Virtual Meeting Link)
 Vijay B Higgins (higgi231@msu.edu)
Knots are determined by their exteriors and producing a triangulation of the exterior given a knot diagram is computationally simple. Taking a three manifold that is a knot exterior however, and turning it into a knot diagram is not. I will discuss a practical algorithm for finding a diagram of a knot, given a triangulation of its exterior. Our method, when given a little bit of extra data, applies to links as well as knots, and allows us to recover links with hundreds of crossings. This is joint work with Nathan Dunfield and Malik Obeidin.

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Combinatorics and Graph Theory
 Jinting Liang, Michigan State University
 Enriched toric $[\vec{D}]$partitions
 12/07/2022
 3:00 PM  3:50 PM
 Online (virtual meeting)
(Virtual Meeting Link)
 Bruce E Sagan (bsagan@msu.edu)
In this talk I will discuss the theory of enriched toric $[\vec{D}]$partitions. Whereas Stembridge's enriched $P$partitions give rises to the peak algebra which is a subring of the ring of quasisymmetric functions QSym, our enriched toric $[\vec{D}]$partitions will generate the cyclic peak algebra which is a subring of cyclic quasisymmetric functions cQSym. In the same manner as the peak set of linear permutations appears when considering enriched $P$partitions, the cyclic peak set of cyclic permutations plays an important role in our theory.
Probability
 Hassan Allouba, Kent State University
 Wellposedness for the KuramotoSivashinsky equation until the 6pth dimension
 12/07/2022
 3:00 PM  3:50 PM
 C405 Wells Hall
 Dapeng Zhan (zhan@msu.edu)
Lately, I’ve been finalizing a couple of papers on the local and global analysis of the KS PDE in multidimensional space. This includes the
well known open problem of the global wellposedness of KS for d ≥ 1. In this talk, I will discuss my Browniantime (or LKS kernel) approach to the Burgers incarnation of the KS equation for all dimensions. This yields a new formulation for the KS equation (deterministic or stochastic), even in the better known one dimensional case. I will then focus on my latest results on the uniqueness and local wellposedness of the KS PDE for d ≥ 1. In particular, I’ll show—using careful estimates on the fundamental LKS kernel—the existence of $L^{2p}$ solution, locally in time, till the 6pth dimension, as well as the global uniqueness of KS solutions. Since this Browniantime setting includes time fractional equations, I will briefly mention the corresponding results for timefractional Burgers equations in multidimensional space—which I’m also finalizing in separate papers. The rest of the global wellposedness results (existence and more) use additional new tools, some of which are inspired in part by my earlier work on Browniantime processes and LKS equations; and I plan to discuss this in the near future. This work—both local and global—is at the heart of other work on the delicate path properties of the SPDEs version of the KS and timefractional Burgers equations, currently under investigation with Yimin Xiao.

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Applied Mathematics
 Rongjie Lai , Rensselaer Polytechnic Institute
 1WMINDS talk (passcode is the first prime number > 100).
 12/08/2022
 2:30 PM  3:30 PM
 Online (virtual meeting)
 Mark A Iwen ()
See https://sites.google.com/view/mindsseminar/home

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Mathematical Physics and Operator Algebras
 Renaud Requipas, NYU
 Estimation of entropy production on the onesided shift
 12/12/2022
 11:00 AM  12:00 PM
 C304 Wells Hall
 Jeffrey Hudson Schenker (schenke6@msu.edu)
Using repeated quantum measurements as a guiding physical example, I will introduce the notion of entropy production for invariant measures on the onesided shift. Then, I will present recent results on a related estimation problem. Informally, this is an attempt at answering the following question: does a typical sequence of outcomes carry a signature of the irreversibility of the stochastic process generating those outcomes?
This is based on joint works (some still in progress) with G. Cristadoro, N. Cunéo, M. Degli Esposti and V. Jaksic.

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Probability
 Adrián HinojosaCalleja, University of Barcelona
 Hitting probabilities and exact modulus of continuity for qisotropic Gaussian random fields
 12/14/2022
 3:00 PM  3:50 PM
 Online (virtual meeting)
(Virtual Meeting Link)
 Dapeng Zhan (zhan@msu.edu)
A Gaussian random field is qisotropic if its associated canonical metric is equivalent to a gauge function q. We develop criteria for hitting probabilities and the existence of a global exact modulus of continuity for such processes. We explore the applications of the criteria to two toy examples: The qBrownian sheet, and the solution to the linear stochastic Poisson equation driven by white noise. This is joint work with Marta SanzSolé.

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Dynamical Systems
 Jing Zhou, Penn State University
 Application of KAM Theory in the FermiUlam Models
 12/16/2022
 2:00 PM  3:00 PM
 C304 Wells Hall
 Huyi Hu (hhu@msu.edu)
In this talk I’ll brief introduce the Fermi acceleration problem and some existing results on the subject. In particular, I’ll discuss how KAM theory has been applied in several variants of the FermiUlam models. I’ll also discuss some open problems in this direction.

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