Erdős-style geometry is concerned with combinatorial questions about simple geometric objects, such as counting incidences between finite sets of points, lines, etc. These questions can be typically viewed as asking for the possible number of...

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Special Year 2022-23: Dynamics, Additive Number Theory and Algebraic Geometry - Seminar

Given $n\in\mathbb{N}$ and $\xi\in\mathbb{R}$, let $\tau(n;\xi)=\sum_{d|n}d^{i\xi}$. Hall and Tenenbaum asked in their book \textit{Divisors} what is the value of $\max_{\xi\in[1,2]} |\tau(n;\xi)|$ for a ``typical'' integer $n$. I will present work...

Sets of recurrence were introduced by Furstenberg in the context
of ergodic theory and have an equivalent combinatorial
characterization as *intersective sets*, an observation
which has led to interesting connections between these areas.

Originally...

Complex dynamics explores the evolution of points under iteration of functions of complex variables. In this talk I will introduce into the context of complex dynamics, a new approximation tool allowing us to construct new examples of entire...

The Mackey-Zimmer representation theorem is a key structural result from ergodic theory: Every compact extension between ergodic measure-preserving systems can be written as a skew-product by a homogeneous space of a compact group. This is used, e.g...

We will discuss a version of the Green--Tao arithmetic regularity lemma and counting lemma which works in the generality of all linear forms. In this talk we will focus on the qualitative and algebraic aspects of the result.

The Gowers uniformity k-norm on a finite abelian group measures the averages of complex functions on such groups over k-dimensional arithmetic cubes. The inverse question about these norms asks if a large norm implies correlation with a function of...

We show that for every positive integer k there are positive constants C and c such that if A is a subset of {1, 2, ..., n} of size at least C n^{1/k}, then, for some d \leq k-1, the set of subset sums of A contains a homogeneous d-dimensional...

Ever since Furstenberg proved his multiple recurrence theorem, the limiting behaviour of multiple ergodic averages along various sequences has been an important area of investigation in ergodic theory. In this talk, I will discuss averages along...

A density theorem for L-functions is quantitative measure of the possible failure of the Riemann Hypothesis. In his 1990 ICM talk, Sarnak introduced the notion of density theorems for families of automorphic forms, measuring the possible failure of...