Seminars Sorted by Series

Workshop on Combinatorics of Enumerative Geometry

Feb
04
2025

Workshop on Combinatorics of Enumerative Geometry

Quilts of Alternating Sign Matrices
Sara Billey
12:00pm|Simonyi Hall 101

Abstract: We present new objects called quilts of alternating sign matrices with respect to two given posets. Quilts generalize several commonly used concepts in mathematics. For example, the rank function on submatrices of a matrix gives rise to a...

Feb
04
2025

Workshop on Combinatorics of Enumerative Geometry

Grothendieck Shenanigans: Algebra Meets Integrable Probability
2:30pm|Simonyi Hall 101

Abstract: In his 2018 paper "Some Schubert shenanigans" Richard Stanley asked for the asymptotic behavior of the maximal principle specialization of a Schubert polynomial. Motivated by this, still open, question we explore the generalization to...

Feb
04
2025

Workshop on Combinatorics of Enumerative Geometry

Tropical psi Classes and Tropicalizations of psi Classes
Renzo Cavalieri
4:30pm|Simonyi Hall 101

Abstract: The general rule for the interactions between tropical geometry and moduli spaces of course is the following: everything you may wish is going to work like a charm in genus zero, and break down horribly in higher genus. This is the case...

Feb
05
2025

Workshop on Combinatorics of Enumerative Geometry

Permutahedral Subdivisions and Class Formulas from Coxeter Elements
Melissa Sherman-Bennett
10:00am|Simonyi Hall 101

Abstract: I will discuss some regular subdivisions of the permutahedron, one for each Coxeter element in the symmetric group. These subdivisions are "Bruhat interval" subdivisions, meaning that each face is the convex hull of the permutations in a...

Feb
05
2025

Workshop on Combinatorics of Enumerative Geometry

Invariants of Lattice Polytopes and Matroids
Eric Katz
12:00pm|Simonyi Hall 101

Abstract: We will discuss invariants of lattice polytopes and their subdivisions arising from Ehrhart and Hodge theory and introduce their matroid theoretic analogues which are enriched versions of the characteristic and Tutte polynomials.

Feb
05
2025

Workshop on Combinatorics of Enumerative Geometry

Chow Quotients of Toric and Schubert Varieties by $\mathbb{C}^*$-actions
2:30pm|Simonyi Hall 101

Abstract: Chow quotients of projective varieties by affine torus actions provide alternative constructions of interesting geometric objects. For example, the moduli space of stable genus 0 curves with $n$ marked points arises as the Chow quotient of...

Feb
06
2025

Workshop on Combinatorics of Enumerative Geometry

Commutative Algebra to Representation Theory, Through the Combinatorics of Filtered RSK
Alex Yong
10:00am|Simonyi Hall 101

Abstract: Suppose $X$ is the affine cone of a projective variety. The Hilbert series of the coordinate ring $C[X]$ is the character of an algebraic torus. More generally, one considers a reductive algebraic group $G$ acting rationally on $X$. When...

Feb
06
2025

Workshop on Combinatorics of Enumerative Geometry

Components of Springer Fibers Equal to Richardson Varieties
Martha Precup
12:00pm|Simonyi Hall 101

Abstract: Springer fibers are subvarieties of the flag variety parameterized by partitions. They are central objects of study in geometric representation theory. Given a partition $λ$, one of the key conclusions of Springer theory is that the top...

Feb
06
2025

Workshop on Combinatorics of Enumerative Geometry

Mirror Symmetry for the Grassmannian and Its Schubert Varieties
Lauren Williams
2:30pm|Simonyi Hall 101

Abstract: While mirror symmetry for flag varieties and Grassmannians has been extensively studied, Schubert varieties in the Grassmannian are singular, and hence standard mirror symmetry statements are not well-defined. Nevertheless, in joint work...

Feb
07
2025

Workshop on Combinatorics of Enumerative Geometry

Geometry of Dyck Paths
Syu Kato
10:00am|Simonyi Hall 101

Abstract: There are two major research trends in the theory of symmetric functions arising from Dyck paths. One is the theory of Catalan symmetric functions and its geometric realization conceived by Chen-Haiman, following the works of Broer and...

Feb
07
2025

Workshop on Combinatorics of Enumerative Geometry

The Picard Group of a Cominuscule Richardson Variety
Anders Buch
12:00pm|Simonyi Hall 101

Abstract: A Richardson variety R in a cominuscule Grassmannian is defined by a skew diagram of boxes. If this diagram has several connected components, then R is a product of smaller Richardson varieties given by the components. I will show that the...

Workshop on Complexity of Proofs and Computations

Workshop on Discrete Geometry and the Kepler Problem

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Feb
27
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Hardy-Littlewood and Chowla Type Conjectures in the Presence of a Siegel Zero
10:00am|Simonyi Hall 101 and Remote Access

Abstract: We discuss some consequences of the existence of a Siegel zero for various questions relating to the distribution of the prime numbers, and in particular to conjectures of Hardy-Littlewood and Chowla type.  This is joint work with Joni...

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Feb
27
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

On Random Polynomials and Counting Number Fields: Fourier Analysis Meets Arithmetic Statistics
Theresa Anderson
2:00pm|Simonyi Hall 101 and Remote Access

Abstract: Behaviors of objects of algebraic interest, such as polynomials, elliptic curves and number fields -- many of which are still unknown -- fall into the field of arithmetic statistics..  By bringing in Fourier analysis to interplay with a...

Feb
28
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Arbitrarily Slow Decay in the Mobius Disjointness Conjecture
10:00am|Simonyi Hall 101 and Remote Access

Abstract: We construct examples showing that the correlation in the Mobius disjointness conjecture can go to zero arbitrarily slowly. In fact, our methods yield a more general result, where in lieu of μ(n) one can put any bounded sequence such that...

Feb
28
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

On a Conjecture of Veech About Möbius Orthogonality
Thierry de la Rue
11:15am|Simonyi Hall 101 and Remote Access

Abstract: In unpublished lecture notes, William A. Veech considered the following potential property of the Möbius function:
"In any Furstenberg system of the Möbius function, the zero-coordinate is orthogonal to any function measurable with respect...

Mar
01
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Thermodynamic Formalism for B-free Dynamical Systems
Joana Kulaga-Przymus
10:00am|Simonyi Hall 101 and Remote Access

Abstract: Given $B \subset N$, we consider the corresponding set $FB$ of $B$-free integers, i.e. $n \inFB i_ no b \in B$ divides $n$. We $de_{ne} X \eta_}$ the B-free subshift _ as the smallest subshift containing $\eta := 1FB \in {0, 1}Z$. Such...

Mar
01
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Distribution of Orbits at Prime and Semi-prime Times
Adam Kanigowski
2:00pm|Simonyi Hall 101 and Remote Access

Abstract: For a topological dynamical systems (T, X) and a fixed $x \in X$ we are interested in the distribution of prime and semi-prime orbits, i.e. ${T px}p='$ and ${T p1p2 x}p1,p2='$. We are interested in systems for which the related sequences...

Mar
01
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Projection Theorems and Applications
3:30pm|Simonyi Hall 101 and Remote Access

Abstract: Given a fractal set E in $R^n$ and a set F in $Gr(k,n)$, can we find k-plane S in F such that the orthogonal projection of E onto S is large? 

We will survey some classical and recent projection theorems and discuss their applications. ...

Mar
02
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Infinite Sumsets in Sets with Positive Density
10:00am|Simonyi Hall 101 and Remote Access

ABSTRACT: In the 1970’s Erdos asked several questions about what kind of infinite structures can be found in every set of natural numbers with positive density. In recent joint work with Kra, Richter and Robertson we proved that every such set A can...

Mar
02
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Polynomial Progressions in Topological Fields and Their Applications to Pointwise Convergence Problems
2:00pm|Simonyi Hall 101 and Remote Access

Abstract: Abstract: We will discuss multilinear variants of Weyl's inequality for the exponential sums arising in pointwise convergence problems related to the Furstenberg-Bergelson-Leibman conjecture. We will also illustrate how to use the...

Mar
02
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Gowers Uniformity of Arithmetic Functions in Short Intervals
4:00pm|Simonyi Hall 101 and Remote Access

Abstract: I will present results establishing cancellation in short sums of arithmetic functions (in particular the von Mangoldt and divisor functions) twisted by polynomial exponential phases, or more general nilsequence phases. These results imply...

Mar
03
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Limit Formulas for Polynomial Ergodic Averages with Commuting Transformations
10:00am|Simonyi Hall 101 and Remote Access

Abstract: The works of Furstenberg and Bergelson-Leibman on the Szemeredi theorem and its polynomial extension motivated the study of the limiting behavior of multiple ergodic averages of commuting transformations with polynomial iterates. Following...

Mar
03
2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Asymptotic Total Ergodicity and Polynomial Patterns in Finite Fields
11:15am|Simonyi Hall 101 and Remote Access

Abstract: A version of the polynomial Szemer´edi theorem was shown to hold in finite fields in [BLM05]. In particular, one has patterns

${x, x + P1(n), . . . , x + Pk(n)}$ (1)

for polynomials with zero constant term in large subsets of finite...

Workshop on Emerging Topics

Workshop on Flows, Foliations and Contact Structures

Dec
07
2015

Workshop on Flows, Foliations and Contact Structures

Floer homology, group orders, and taut foliations of hyperbolic 3-manifolds
Nathan Dunfeld
10:00am|Simonyi Hall 101
A bold conjecture of Boyer-Gorden-Watson and others posit that for any irreducible rational homology 3-sphere M the following three conditions are equivalent: (1) the fundamental group of M is left-orderable, (2) M has non-minimal Heegaard Floer...
Dec
07
2015

Workshop on Flows, Foliations and Contact Structures

Contact Structures, foliations and group actions
Jonathan Bowdan
11:30am|Simonyi Hall 101
We use contact deformations to study the topology of the space of taut foliations and group actions on the circle.
Dec
07
2015

Workshop on Flows, Foliations and Contact Structures

Positive-definite symplectic four-manifolds
2:30pm|Simonyi Hall 101
We give new constraints on the topology of symplectic four-manifolds using invariants from Heegaard Floer homology. In particular, we will prove that certain simply-connected four-manifolds with positive-definite intersection forms cannot admit...