Seminars Sorted by Series

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Mar

2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Higher Order Sumsets in Sets of Positive Density

11:15am|Simonyi Hall 101 and Remote Access

Abstract: In this talk we present a natural generalization of a sumset conjecture of Erdos to higher orders, asserting that every subset of the integers with positive density contains a sumset $B_1+\ldots +B_k$ where $B_1, \ldots , B_k$ are infinite...

Mar

2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Polynomial Progressions in Topological Fields and Their Applications to Pointwise Convergence Problems

Mariusz Mirek

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

2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Gowers Uniformity of Arithmetic Functions in Short Intervals

Joni Teräväinen

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

2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Limit Formulas for Polynomial Ergodic Averages with Commuting Transformations

Nikos Frantzikinakis

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

2023

Workshop on Dynamics, Discrete Analysis and Multiplicative Number Theory

Asymptotic Total Ergodicity and Polynomial Patterns in Finite Fields

Vitaly Bergelson

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

Oct

2016

Workshop on Emerging Topics

To Be Announced

9:00am

Nov

2016

Workshop on Emerging Topics

To Be Announced

9:00am|S-101

Nov

2016

Workshop on Emerging Topics

To Be Announced

9:00am

Nov

2016

Workshop on Emerging Topics

To Be Announced

9:00am

Nov

2016

Workshop on Emerging Topics

To Be Announced

9:00am

Workshop on Flows, Foliations and Contact Structures

Dec

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

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

2015

Workshop on Flows, Foliations and Contact Structures

Positive-definite symplectic four-manifolds

Jennifer Hom

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...

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Tight, non-fillable contact structures on 3-manifolds

Andy Wand

4:00pm|Simonyi Hall 101

The modern development of contact geometry in 3 dimensions has seen several (due to Giroux, Wendl, Latschev and Wendl, Hutchings, and others) invariants of contact structures meant in some sense to measure non-(Stein /symplectic)-fillability of the...

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Quasigeodesic pseudo-Anosov flows in hyperbolic 3-manifolds

Sergio Fenley

10:00am|Simonyi Hall 101

We obtain a simple topological and dynamical systems condition which is necessary and sufficient for an arbitrary pseudo-Anosov flow in a closed, hyperbolic three manifold to be quasigeodesic. Quasigeodesic means that orbits are efficient in...

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Floer homology and covering spaces

Ciprian Manolescu

11:30am|Simonyi Hall 101

I will discuss a Smith-type inequality for regular covering spaces in monopole Floer homology. Using the monopole Floer / Heegaard Floer correspondence, it follows that if a 3-manifold Y admits a p^n-sheeted regular cover that is a Z/p-L-space (for...

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Uniqueness of the contact structure approximating a foliation

Thomas Vogel

2:30pm|Simonyi Hall 101

A well known result of Eliashberg and Thurston states that smooth foliations can be approximated by contact structures. We discuss the uniqueness of this contact structure and applications.

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Curvature and contact topology

Patrick Massot

4:00pm|Simonyi Hall 101

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Symplectic fillability of contact graph manifolds via line arrangements

Laura Starkston

10:00am|Simonyi Hall 101

An interesting aspect of the classification of symplectic fillings of Seifert fibered spaces is the appearance of complex and symplectic line arrangements in CP2. Line arrangements have been studied classically for decades and have intricate...

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Taut foliations and cyclic branched covers

Cameron Gordon

11:30am|Simonyi Hall 101

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Convex surfaces and grid diagrams

Ivan Dynnikov

2:30pm|Simonyi Hall 101

I will speak about a simple way to represent surfaces in the three-space by diagrams similar to rectangular diagrams of links. A set of moves will be given by which one can connect any two diagrams representing isotopic surfaces. By forbidding some...

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Contact structures and reducible surgeries

Tye Lidman

4:00pm|Simonyi Hall 101

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Contact homology and virtual fundamental cycles

John Pardon

10:00am|Simonyi Hall 101

Contact homology is a powerful invariant of contact manifolds introduced by Eliashberg--Givental--Hofer. The definition involves certain counts of pseudo-holomorphic curves, however these are usually only "virtual" counts since the moduli spaces of...

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Foliations on graph manifolds, orderability and L-spaces

Steve Boyer

11:30am|Simonyi Hall 101

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Coarse hyperbolicity and closed orbits for quasigeodesic flows

Steve Frankel

2:30pm|Simonyi Hall 101

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Definite surfaces and alternating links

Josh Greene

4:00pm|Simonyi Hall 101

Dec

2015

Workshop on Flows, Foliations and Contact Structures

Taut co-oriented foliations

Rachel Roberts

10:00am|Simonyi Hall 101

Eliashberg and Thurston proved that the tangent plane field of any C2 taut oriented foliation F≠S1×S2 can be C0 approximated by a pair of particularly nice smooth contact structures. Kazez and Roberts proved that the requirement that F be C2 can be...

Dec

2015