| Talk_id | Date | Speaker | Title |
|
26835
|
Thursday 1/7
2:30 PM
|
Jose Perea, Michigan State University
|
TBA; zoom link @ https://sites.google.com/view/minds-seminar/home
- Jose Perea, Michigan State University
- TBA; zoom link @ https://sites.google.com/view/minds-seminar/home
- 01/07/2021
- 2:30 PM - 3:30 PM
-
(Virtual Meeting Link)
- Olga Turanova (turanova@msu.edu)
No abstract available.
|
|
26848
|
Thursday 1/14
3:30 PM
|
Raymond Chan, City University of Hong Kong
|
TBA; zoom link @ https://sites.google.com/view/minds-seminar/home
- Raymond Chan, City University of Hong Kong
- TBA; zoom link @ https://sites.google.com/view/minds-seminar/home
- 01/14/2021
- 3:30 PM - 4:30 PM
-
(Virtual Meeting Link)
- Olga Turanova (turanova@msu.edu)
TBA; (Note the unusual time: 4:30pm Shanghai, 10:30am Paris.)
|
|
26940
|
Wednesday 1/20
3:00 PM
|
Sergi Elizalde, Dartmouth College
|
Descents on quasi-Stirling permutations
- Sergi Elizalde, Dartmouth College
- Descents on quasi-Stirling permutations
- 01/20/2021
- 3:00 PM - 3:50 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Bruce E Sagan (bsagan@msu.edu)
Stirling permutations were introduced by Gessel and Stanley to give a combinatorial interpretation of certain polynomials related to Stirling numbers. A very natural extension of Stirling permutations are quasi-Stirling permutations, which are in bijection with labeled rooted plane trees. Archer et al. introduced these permutations, and conjectured that there are $(n+1)^{n-1}$ quasi-Stirling permutations of size $n$ having $n$ descents.
In this talk we prove this conjecture. More generally, we give the generating function for quasi-Stirling permutations by the number of descents, which turns out to satisfy a beautiful equation involving Eulerian polynomials. We show that some of the properties of descents on usual permutations and on Stirling permutations have an analogue for quasi-Stirling permutations.
Finally, we extend our results to a one-parameter family of permutations, called $k$-quasi-Stirling permutations, which are in bijection with certain decorated trees.
|
|
26961
|
Thursday 1/21
2:30 PM
|
Daniel Kane, University of California, San Diego
|
Point Location and Active Learning
- Daniel Kane, University of California, San Diego
- Point Location and Active Learning
- 01/21/2021
- 2:30 PM - 3:30 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Olga Turanova (turanova@msu.edu)
In the point location problem one is given a hyperplane arrangement and an unknown point. By making linear queries about that point one wants to determine which cell of the hyperplane arrangement it lies in. This problem has an unexpected connection to the problem in machine learning of actively learning a halfspace. We discuss these problems and their relationship and provide a new and nearly optimal algorithm for solving them.
|
|
26969
|
Friday 1/22
5:00 PM
|
Zheng Xiao, MSU
|
Extensions of function fields
- Zheng Xiao, MSU
- Extensions of function fields
- 01/22/2021
- 5:00 PM - 6:00 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Zheng Xiao (xiaozhen@msu.edu)
No abstract available.
|
|
26973
|
Tuesday 1/26
10:00 AM
|
|
Online large lectures and coordinated courses - challenges and opportunities
-
- Online large lectures and coordinated courses - challenges and opportunities
- 01/26/2021
- 10:00 AM - 11:00 AM
-
(Virtual Meeting Link)
- Tsvetanka Sendova (tsendova@msu.edu)
No abstract available.
|
|
26968
|
Tuesday 1/26
2:50 PM
|
Matt Stoffregen, MSU
|
Surgery Exact Triangles in Involutive Floer homology
- Matt Stoffregen, MSU
- Surgery Exact Triangles in Involutive Floer homology
- 01/26/2021
- 2:50 PM - 3:40 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Honghao Gao (gaohongh@msu.edu)
We'll sketch the definition of the involutive Heegaard Floer homology constructed by Hendricks-Manolescu, and then explain how this homology theory behaves under surgery. As a consequence, we can use the surgery formula to construct three-manifolds which are not homology cobordant to any combination of Seifert fiber spaces. This is joint work Kristen Hendricks, Jen Hom and Ian Zemke.
|
|
26943
|
Tuesday 1/26
4:30 PM
|
Luis Silvestre, University of Chicago
|
Integro-differential diffusion and the Boltzmann equation
- Luis Silvestre, University of Chicago
- Integro-differential diffusion and the Boltzmann equation
- 01/26/2021
- 4:30 PM - 5:30 PM
- Online (virtual meeting)
- Aaron D Levin (levina@msu.edu)
Integro-differential equations have been a very active area of research in the last 20 years. In this talk we will explain what they are and in what sense they are similar to more classical parabolic partial differential equations. We will discuss results on regularity estimates for the Boltzmann equation in this context.
|
|
26941
|
Wednesday 1/27
3:00 PM
|
Joshua Swanson, UCSD
|
DUSTPAN distributions as limit laws for Mahonian statistics on forests
- Joshua Swanson, UCSD
- DUSTPAN distributions as limit laws for Mahonian statistics on forests
- 01/27/2021
- 3:00 PM - 3:50 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Bruce E Sagan (bsagan@msu.edu)
Building on work of Stanley and Björner-Wachs, we study the distribution of certain Mahonian statistics on several families of posets, including the major index on linear extensions of forests. We show that the resulting standardized distributions are often asymptotically normal. However, in certain regimes, we must introduce a new, closed family of continuous probability distributions called DUSTPAN distributions which simultaneously generalize the Irwin-Hall and normal distributions. In the case of forests, we use graph-theoretic statistics like height and elevation to completely determine the precise limit laws. This leads to some natural open questions about the distribution of the height of such forests.
Joint work with Sara Billey (https://arxiv.org/abs/2010.12701) building on earlier joint work with Sara Billey and Matjaž Konvalinka (https://arxiv.org/abs/1905.00975).
|
|
26960
|
Wednesday 1/27
4:00 PM
|
Vaidehee Thatte, SUNY Binghamton
|
Arbitrary Valuation Rings and Wild Ramification
- Vaidehee Thatte, SUNY Binghamton
- Arbitrary Valuation Rings and Wild Ramification
- 01/27/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Preston Wake (wakepres@msu.edu)
We aim to develop ramification theory for arbitrary valuation fields, extending the classical theory of complete discrete valuation fields with perfect residue fields. By studying wild ramification, we hope to understand the mysterious phenomenon of the $\textit{defect}$ (or ramification deficiency) unique to the positive residue characteristic case and is one of the main obstacles in obtaining resolution of singularities.
Extensions of degree $p$ in residue characteristic $p>0$ are building blocks of the general case. We present a generalization of ramification invariants for such extensions. These results enable us to construct an upper ramification filtration of the absolute Galois group of Henselian valuation fields (joint with K.Kato).
|
|
26970
|
Wednesday 1/27
4:00 PM
|
Keshav Sutrave, Michigan State University
|
An intro to Riemann surfaces: What your complex analysis prof. doesn’t want you to know
- Keshav Sutrave, Michigan State University
- An intro to Riemann surfaces: What your complex analysis prof. doesn’t want you to know
- 01/27/2021
- 4:00 PM - 5:00 PM
-
- Danika Van Niel (vannield@msu.edu)
Riemann surfaces blend together complex analysis, geometry, and topology (and then eventually connect to PDE’s, algebraic geometry & number theory, and probably everything else).
I will only scratch the surface by introducing them, as well as the notions of branched covering, monodromy, and the Riemann-Hurwitz formula.
Zoom link: https://msu.zoom.us/j/91485321701
Password: SGTS
|
|
26962
|
Thursday 1/28
3:30 AM
|
Zuowei Shen, National University of Singapore
|
Deep Approximation via Deep Learning
- Zuowei Shen, National University of Singapore
- Deep Approximation via Deep Learning
- 01/28/2021
- 3:30 AM - 4:30 AM
- Online (virtual meeting)
(Virtual Meeting Link)
- Olga Turanova (turanova@msu.edu)
The primary task of many applications is approximating/estimating a function through samples drawn from a probability distribution on the input space. The deep approximation is to approximate a function by compositions of many layers of simple functions, that can be viewed as a series of nested feature extractors. The key idea of deep learning network is to convert layers of compositions to layers of tuneable parameters that can be adjusted through a learning process, so that it achieves a good approximation with respect to the input data. In this talk, we shall discuss mathematical theory behind this new approach and approximation rate of deep network; how this new approach differs from the classic approximation theory, and how this new theory can be used to understand and design deep learning network.
|
|
26981
|
Friday 1/29
1:00 PM
|
Nick Rekuski, MSU
|
Etale Cohomology I: Preliminary
- Nick Rekuski, MSU
- Etale Cohomology I: Preliminary
- 01/29/2021
- 1:00 PM - 2:00 PM
- Online (virtual meeting)
- Chuangtian Guan (guanchua@msu.edu)
No abstract available.
|
|
26974
|
Friday 1/29
5:00 PM
|
Zheng Xiao, MSU
|
$ef$ Theorem, discriminant and different in function fields
- Zheng Xiao, MSU
- $ef$ Theorem, discriminant and different in function fields
- 01/29/2021
- 5:00 PM - 6:00 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Zheng Xiao (xiaozhen@msu.edu)
No abstract available.
|
|
26976
|
Tuesday 2/2
10:00 AM
|
Jamillah Gross-Caldwell, MSU
|
About the Michigan Louis Stokes Alliance for Minority Participation in STEM and MSU NxtGen STEM Scholars Program
- Jamillah Gross-Caldwell, MSU
- About the Michigan Louis Stokes Alliance for Minority Participation in STEM and MSU NxtGen STEM Scholars Program
- 02/02/2021
- 10:00 AM - 11:00 AM
-
(Virtual Meeting Link)
- Tsvetanka Sendova (tsendova@msu.edu)
No abstract available.
|
|
26944
|
Tuesday 2/2
4:00 PM
|
Samit Dasgupta, Duke University
|
Stark's Conjectures and Hilbert's 12th Problem
- Samit Dasgupta, Duke University
- Stark's Conjectures and Hilbert's 12th Problem
- 02/02/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Aaron D Levin ()
In this talk we will discuss two central problems in algebraic number theory and their interconnections: explicit class field theory (also known as Hilbert's 12th Problem), and the special values of L-functions. The goal of explicit class field theory is to describe the abelian extensions of a ground number field via analytic means intrinsic to the ground field. Meanwhile, there is an abundance of conjectures on the special values of L-functions at certain integer points. Of these, Stark's Conjecture has special relevance toward explicit class field theory. I will describe my recent proof, joint with Mahesh Kakde, of the Brumer-Stark conjecture away from p=2. This conjecture states the existence of certain canonical elements in CM abelian extensions of totally real fields. Next I will describe our proof of an exact formula for these Brumer-Stark units that had been developed by many authors over the last 15 years. We show that the Brumer-Stark units along with other elementary quantities generate the maximal abelian extension of totally real number fields, thereby giving a solution to Hilbert's 12th problem for these fields.
|
|
26975
|
Wednesday 2/3
3:00 PM
|
Richard Stanley, MIT
|
Two Analogues of Pascal's Triangle
- Richard Stanley, MIT
- Two Analogues of Pascal's Triangle
- 02/03/2021
- 3:00 PM - 3:50 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Bruce E Sagan (bsagan@msu.edu)
Pascal's triangle is closely associated with the expansion of
the product $(1+x)^n$. We will discuss two analogous arrays of numbers
that are associated with the products
$\prod_{i=0}^{n-1} \left(1+x^{2^i}+x^{2^{i+1}}\right)$ and
$\prod_{i=1}^n \left(1+x^{F_{i+1}}\right)$, where $F_{i+1}$ is a Fibonacci
number. All three arrays are special cases of a two-parameter family that
might be interesting to investigate further.
|
|
26963
|
Thursday 2/4
2:30 PM
|
Tino Ullrich , TU Chemnitz
|
A New Subsampling Technique for Random Points and Optimal Least Squares Approximation of High-Dimensional Functions
- Tino Ullrich , TU Chemnitz
- A New Subsampling Technique for Random Points and Optimal Least Squares Approximation of High-Dimensional Functions
- 02/04/2021
- 2:30 PM - 3:30 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Olga Turanova (turanova@msu.edu)
We provide a new general upper bound for the minimal L2-worst-case recovery error in the framework of RKHS, where only n function samples are allowed. This quantity can be bounded in terms of the singular numbers of the compact embedding into the space of square integrable functions. It turns out that in many relevant situations this quantity is asymptotically only worse by square root of log(n) compared to the singular numbers. The algorithm which realizes this behavior is a weighted least squares algorithm based on a specific set of sampling nodes which works for the whole class of functions simultaneously. These points are constructed out of a random draw with respect to distribution tailored to the spectral properties of the reproducing kernel (importance sampling) in combination with a sub-sampling procedure coming from the celebrated proof of Weaver's conjecture, which was shown to be equivalent to the Kadison-Singer problem. For the above multivariate setting, it is still a fundamental open problem whether sampling algorithms are as powerful as algorithms allowing general linear information like Fourier or wavelet coefficients. However, the gap is now rather small. As a consequence, we may study well-known scenarios where it was widely believed that sparse grid sampling recovery methods perform optimally. It turns out that this is not the case for dimensions d > 2.
This is joint work with N. Nagel and M. Schaefer from TU Chemnitz.
|
|
26942
|
Tuesday 2/9
2:50 PM
|
Irving Dai, MIT
|
TBA
|
|
26950
|
Tuesday 2/9
4:00 PM
|
Jordan Ellenberg, University of Wisconsin–Madison
|
TBA
- Jordan Ellenberg, University of Wisconsin–Madison
- TBA
- 02/09/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Aaron D Levin ()
TBA
|
|
26954
|
Wednesday 2/10
4:00 PM
|
Tudor Padurariu, IAS
|
TBA
- Tudor Padurariu, IAS
- TBA
- 02/10/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Laure Flapan (flapanla@msu.edu)
TBA
|
|
26964
|
Thursday 2/11
2:30 PM
|
Massimo Fornasier , Technische Universität München
|
TBA
- Massimo Fornasier , Technische Universität München
- TBA
- 02/11/2021
- 2:30 PM - 3:30 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Olga Turanova (turanova@msu.edu)
No abstract available.
|
|
26953
|
Tuesday 2/16
2:50 PM
|
Linh Truong, University of Michigan
|
TBA
- Linh Truong, University of Michigan
- TBA
- 02/16/2021
- 2:50 PM - 3:40 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Honghao Gao (gaohongh@msu.edu)
TBA
|
|
26971
|
Tuesday 2/16
4:00 PM
|
Walter Strauss, Brown University
|
TBA
- Walter Strauss, Brown University
- TBA
- 02/16/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Aaron D Levin ()
TBA
|
|
26957
|
Wednesday 2/17
4:00 PM
|
François Greer, IAS
|
A tale of two Severi curves
- François Greer, IAS
- A tale of two Severi curves
- 02/17/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Laure Flapan (flapanla@msu.edu)
No abstract available.
|
|
26951
|
Tuesday 2/23
2:50 PM
|
Thang Le, Georgia Tech
|
TBA
|
|
26958
|
Wednesday 2/24
4:00 PM
|
Ignacio Barros, Université Paris-Saclay
|
TBA
- Ignacio Barros, Université Paris-Saclay
- TBA
- 02/24/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Laure Flapan (flapanla@msu.edu)
No abstract available.
|
|
26967
|
Tuesday 3/2
2:50 PM
|
Break Day, no talk
|
No talk
- Break Day, no talk
- No talk
- 03/02/2021
- 2:50 PM - 3:40 PM
- Online (virtual meeting)
- Honghao Gao (gaohongh@msu.edu)
No abstract available.
|
|
26956
|
Wednesday 3/3
4:00 PM
|
Rankeya Datta, University of Illinois at Chicago
|
TBA
- Rankeya Datta, University of Illinois at Chicago
- TBA
- 03/03/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Joe Waldron (waldro51@msu.edu)
No abstract available.
|
|
26966
|
Tuesday 3/9
2:50 PM
|
Roger Casals, UC Davis
|
TBA
|
|
26945
|
Tuesday 3/9
4:00 PM
|
Andrea Nahmod, University of Massachusetts Amherst
|
TBA
- Andrea Nahmod, University of Massachusetts Amherst
- TBA
- 03/09/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Aaron D Levin ()
TBA
|
|
26978
|
Tuesday 3/16
2:50 PM
|
Keegan Boyle, UBC
|
TBA
|
|
26946
|
Tuesday 3/16
4:00 PM
|
Martin Olsson, UC Berkeley
|
TBA
- Martin Olsson, UC Berkeley
- TBA
- 03/16/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Aaron D Levin ()
TBA
|
|
26955
|
Wednesday 3/17
4:00 PM
|
Daniel Bragg, University of California, Berkeley
|
TBA
- Daniel Bragg, University of California, Berkeley
- TBA
- 03/17/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Rajesh S Kulkarni (kulkar23@msu.edu)
No abstract available.
|
|
26977
|
Wednesday 3/24
4:00 PM
|
Stefan Patrikis, Ohio State University
|
TBA
- Stefan Patrikis, Ohio State University
- TBA
- 03/24/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Igor Rapinchuk (rapinchu@msu.edu)
No abstract available.
|
|
26980
|
Tuesday 3/30
11:00 AM
|
Renaud Detcherry, Bourgogne
|
TBA
- Renaud Detcherry, Bourgogne
- TBA
- 03/30/2021
- 11:00 AM - 11:50 AM
- Online (virtual meeting)
(Virtual Meeting Link)
- Honghao Gao (gaohongh@msu.edu)
TBA
|
|
26979
|
Tuesday 4/6
2:50 PM
|
Charlie Frohman, U Iowa
|
TBA
|
|
26947
|
Tuesday 4/6
4:00 PM
|
Emily Riehl, Johns Hopkins University
|
TBA
- Emily Riehl, Johns Hopkins University
- TBA
- 04/06/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Aaron D Levin ()
TBA
|
|
26952
|
Wednesday 4/7
4:00 PM
|
Sarah Frei, Rice University
|
TBA
- Sarah Frei, Rice University
- TBA
- 04/07/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Rajesh S Kulkarni (kulkar23@msu.edu)
No abstract available.
|
|
26972
|
Tuesday 4/13
2:50 PM
|
Mustafa Hajij, Santa Clara University
|
TBA
- Mustafa Hajij, Santa Clara University
- TBA
- 04/13/2021
- 2:50 PM - 3:40 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Honghao Gao (gaohongh@msu.edu)
TBA
|
|
26948
|
Tuesday 4/13
4:00 PM
|
Adrian Ioana, UC San Diego
|
TBA
- Adrian Ioana, UC San Diego
- TBA
- 04/13/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Aaron D Levin ()
TBA
|
|
26959
|
Wednesday 4/14
4:00 PM
|
Yihang Zhu, University of Maryland
|
TBA
- Yihang Zhu, University of Maryland
- TBA
- 04/14/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Igor Rapinchuk (rapinchu@msu.edu)
No abstract available.
|
|
26982
|
Tuesday 4/20
2:50 PM
|
Hannah Schwartz, Princeton
|
TBA
- Hannah Schwartz, Princeton
- TBA
- 04/20/2021
- 2:50 PM - 3:40 PM
- Online (virtual meeting)
(Virtual Meeting Link)
- Honghao Gao (gaohongh@msu.edu)
TBA
|
|
26949
|
Tuesday 4/20
4:00 PM
|
Nicolas Addington, University of Oregon
|
TBA
- Nicolas Addington, University of Oregon
- TBA
- 04/20/2021
- 4:00 PM - 5:00 PM
- Online (virtual meeting)
- Aaron D Levin ()
TBA
|
