Seminars Sorted by Series
Members' Colloquium
Zeroes of Characters (cf. J.-P. Serre, same title, arXiv 2312.17551)
1:00pm|Simonyi 101 and Remote Access
A promenade in Serre's paper, plus some related results of
mine.
"Local-to-global" Theorems On High Dimensional Expanders
1:00pm|Simonyi 101 and Remote Access
Expansion in graphs is a well studied topic, with a wealth of
applications in many areas of mathematics and the theory of
computation.
High dimensional expansion is a generalization of expansion from
graphs to higher dimensional objects, such as...
Challenges and Breakthroughs in the Mathematics of Plasmas
1:00pm|Simonyi 101 and Remote Access
This colloquium will explore some fundamental issues in the
mathematics of plasmas, focusing on the stability and instability
of solutions to Vlasov-type equations, which are crucial for
describing the behavior of charged particles in a plasma. A...
Relationships Between Nilpotency and Curvature
1:00pm|Simonyi 101 and Remote Access
We travel the years in order to understand the relationship
between Nilpotency and Riemannian geometry: including Gromov's
almost flat theorem for manifolds with bounded curvature and
Fukaya-Yamaguchi's almost nilpotency of spaces with lower...
Poisson Boundary, Liouville Property and Asymptotic Geometry of Linear Groups
1:00pm|Simonyi 101 and Remote Access
The Poisson-Furstenberg boundary is a measure space that
describes asymptotics of infinite trajectories of random walks.
The boundary is non-trivial if and only if the defining
measure admits non-constant bounded harmonic
functions.
The origin of...
Around the Alexandrov-Fenchel Inequality
1:00pm|Simonyi 101 and Remote Access
In the late 1800s, in the course of his study of classical
problems of number theory, the young Hermann Minkowski discovered
the importance of a new kind of geometric object that we now call a
convex set. He soon developed a rich theory for...
Quantitative Stability of Geometric Inequalities: Pr\'ekopa-Leindler and Borell-Brascamp-Lieb
1:00pm|Simonyi 101 and Remote Access
The Prékopa-Leindler inequality (PL) and its strengthening, the
Borell-Brascamp-Lieb inequality, are functional extensions of the
Brunn-Minkowski inequality from convex geometry, which itself
refines the classical isoperimetric inequality. These...
Inequalities For Trees and Matroids
1:00pm|Simonyi 101 and Remote Access
In their 1971 study of telephone switching circuitry, Graham and
Pollak designed a novel addressing scheme that was better suited
for the faster communication required by computers. They introduced
the distance matrix of a graph, and used its...
Erd\H{o}s Unit Distance Problem and Graph Rigidity
1:00pm|Simonyi 101 and Remote Access
Erd\H{o}s unit distance problem asks the following: Let $P$ be a
set of $n$ distinct points in the plane, and let $U(P)$ denote the
number of pairs of points in $P$ that are at distance 1. How large
can $U(P)$ be? In 1946, Erd\H{o}s showed that for...
1:00pm|Simonyi 101 and Remote Access
1:00pm|Simonyi 101 and Remote Access
1:00pm|Simonyi 101 and Remote Access
1:00pm|Simonyi 101 and Remote Access
1:00pm|Simonyi 101 and Remote Access
1:00pm|Simonyi 101 and Remote Access
1:00pm|Simonyi 101 and Remote Access
1:00pm|Simonyi 101 and Remote Access
Members’ Seminar
Completing the Bernstein Program (A Geometric Conjecture within the Representation Theory of p-adic Groups)
Approximation algorithms and Grothendieck type inequalities
I will describe a connection between a classical inequality of
Grothendieck and approximation algorithms based on semi-definite
programming. The investigation of this connection suggests the
definition of a new graph parameter, called the...
Local Models of Shimura Varieties
George Pappas
Blow up in a 3-D "toy" model for the Euler equations
We present a 3-D vector dyadic model given in terms of an
infinite system of nonlinearly coupled ODE. This toy model is
inspired by approximations to the fluid equations studied by
Dinaburg and Sinai. The model has structural similarities with
the...
A New Characterization of Sobolev Spaces
This talk is motivated by some recent work of Bourgain-
rezis-Mironescu. A few years ago, they introduced an elementary way
of defining the Sobolev spaces $W^{1,p}$ without making any use of
derivatives. I will present their definition and some...
p-Adic Multiple Zeta Values
A Liouville Type Result for some Conformally Invariant Fully Nonlinear Equations
I will talk about some joint work with Yanyan Li which extended
the Liouville type theorem of Caffarelli-Gidas-Spruck's on the
Yamabe equation to the fully nonlinear case.
Polynomiality Properties of Type A Weight and Tensor Product Multiplicities
Kostka numbers and Littlewood-Richardson coefficients appear in
the representation theory of complex semisimple Lie algebras of
type A, respectively as the multiplicities of weights in
irreducible representations, and the multiplicities of...
Exotic Smooth Structures on Rational Surfaces
Most known smoothable simply connected 4--manifolds admit
infinitely many different smooth structures (distinguished, for
example, by Seiberg--Witten invariants). There are some
4--manifolds, though, for which the existence of such
'exotic'...
Iterated Integrals and Algebraic Cycles
It will be on some constructions in the candidate category of
mixed Tate Motives constructed by Bloch and Kriz.
Motivic Integration, Constructible Functions, and Stringy Chern Classes
In this talk I will discuss a joint work with Lupercio, Nevins
and Uribe, in which we use motivic integration to give a theory of
Chern classes for singular algebraic varieties that is birationally
well-behaved (i.e., with a "stringy" flavor). The...
On some Properties of the Nottingham Group
Let F be a finite field. The Nottingham group N(F) is the group
of formal power series \{ t(1+a_1 t + a_2 t^2 + ...): a_i \in F
\}or, equivalently, the group of wild automorohisms of the local
field F((t)). In spite of such a simple definition, the...
Generalized Teichmueller Spaces
Classical Teichmueller space parametrizes complex structures on
a Riemann surface of genus g>1. Recently several generalized
Teichmueller spaces have been defined and studied by very different
approaches. Nevertheless, some of the results are...
Quantitative Symplectic Geometry
Universality for Mathematical and Physical Systems
Percy Deift
All physical systems in equilibrium obey the laws of
thermodynamics. In other words, whatever the precise nature of the
interaction between the atoms and molecules at the microscopic
level, at the macroscopic level, physical systems exhibit...
Random Walks and Equidistribution on Lie Groups
I will discuss various issues related to the local problem on
Lie groups, the asymptotics of the return probablity, and the
equidistribution of dense subgroups.
The Deligne-Simpson Problem and Double Affine Hecke Algebras
Let us fix $m$ conjugacy classes $C_1,\dots,C_m$ inside $GL(n)$.
The variety of $m$-tuple of matrices such that: $$X_i\in C_i, \quad
i=1,\dots,m mbox{ and } X_1\dots X_m=1.$$ is a solution of the
Deligne-Simpson problem. Double affine Hecke algebras...
Deformation of Yang-Mills Theory Via Pure Spinors
Arithmetic Progressions and Nilmanifolds
Multivariable Mahler Measure and Regulators
The Mahler measure of an n-variable polynomial P is the integral
of log|P| over the n-dimensional unit torus T^n with the Haar
measure. For one-variable polynomials, this is a natural quantity
that appears in different problems such as Lehmer's...
Counting Polynomial Configurations on Dense Subsets of the Integers
The polynomial Szemeredi theorem of Bergelson and Leibman states
that every integer subset with positive density contains infinitely
many configurations of the form x,x+p_1(n),...x+p_k(n), where
p_1,...,p_k is any fixed family of integer polynomials...
Generation of Finite Simple Groups and Derangements
We will first discuss some results on generation of finite
simple groups. Using the classification of finite simple grouops,
one can prove the following results: Every finite simple can be
generated by two elements and the probability that a pair of...
String Topology and Closed Geodesics
Expository talk on work in progress. M.Chas and D.Sullivan
introduced a product on the homology of the free loop spaace of a
compact, oriented manifold M that has also been studied by
R.L.Cohen, V.Godin, J.D.S.Jones, J.Klein, and others. If M
is...
A fake projective space is a smooth complex projective algebraic
variety which is uniformized by the unit ball in $\mathbb C^n$ and
whose Betti numbers are the same as that of $\mathbb
P^n_{\mathbb{C}}$. The first example of a fake projective
plane...
Some Results on Complete Symmetric Varieties
Let G be a semisimple adjoint group. There is a partition of its
wonderful compactification into finitely many G-stable pieces,
which was introduced by Lusztig. Each piece is a locally trivial
fibration over a partial flag variety with fibres...
On the p-Adic Spectra of Some Hecke Operators
I'll first summarize my conjecture about the p-adic slopes of
modular forms for GL_2 (both classical and overconvergent). This
conjecture is based upon some structures in the geometry of the
special fibers of elliptic modular curves at p. In an...
The Two-Dimensional Ising Model and SLE
Open Gromov-Witten Theory of the Quintic Threefold
Recently, I defined an open Gromov-Witten invariant for
Lagrangian submanifolds that arise as the real points of a real
symplectic manifold. In this talk, I will discuss a calculation of
the genus zero open Gromov-Witten theory of the Fermat type...
Equidistribution Problems on Siegel Modular Varieties
In this talk, I'd like to discuss an intriguing equidistribution
property of automorphic forms on arithmetic quotients of
homogeneous varieties, focusing on cuspidal Hecke eigenforms for
Sp(n, Z), the Siegel modular group of genus n. Our approach
is...
We introduce and construct the "AC geometry" from the Gaussian
free field and use it to prove various facts about Schramm-Loewner
evolutions.
Random Geometry and SLE II
We introduce and construct the "AC geometry" from the Gaussian
free field and use it to prove various facts about Schramm-Loewner
evolutions.
Regularity and Analyticity for the dissipative Quasi-Geostrophic Equations
The Generalized de Rham-Witt Complex Over a Field is a Complex of Zero-Cycles