Seminars Sorted by Series

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Abstract: In unpublished lecture notes, William A. Veech considered the following potential property of the Möbius function: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...
Dec
07
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
08
2015

Workshop on Flows, Foliations and Contact Structures

Quasigeodesic pseudo-Anosov flows in hyperbolic 3-manifolds
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
08
2015

Workshop on Flows, Foliations and Contact Structures

Floer homology and covering spaces
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
08
2015

Workshop on Flows, Foliations and Contact Structures

Uniqueness of the contact structure approximating a foliation
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
09
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
09
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
10
2015

Workshop on Flows, Foliations and Contact Structures

Contact homology and virtual fundamental cycles
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
11
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...

Workshop on Fundamental Groups and Periods