# Special Year Research Seminar

### The Erdős-Szekeres problem in three (and higher) dimensions

Finding the smallest integer N=ES_d(n) such that in every configuration of N points in R^d in general position there exist n points in convex position is one of the most classical problems in extremal combinatorics, known as the Erdős-Szekeres...

### On Furstenberg systems for some aperiodic multiplicative functions

The Chowla conjecture from 1965 predicts that all autocorrelations of the Liouville function vanish. In fact, after an adaptation, the Chowla conjecture was expected to hold for all aperiodic multiplicative functions with values in the unit disc (cf...

### Toward Classifying Reducts of the Complex Field

Chieu-Minh Tran

We discuss some recent progress on the model-theoretic problem of classifying the reducts of the complex field (with named parameters and up to interdefinability). The tools we use include Castle’s recent solution of the Restricted Trichotomy...

### Products of primes in arithmetic progressions

A conjecture of Erdős states that for every large enough prime q, every reduced residue class modulo q is the product of two primes less than q. I will discuss my on-going work with Kaisa Matomäki establishing among other things a ternary variant of...

### Almost all dynamically syndetic sets are multiplicatively thick

Daniel Glasscock

If a set of integers is syndetic (finitely many translates cover the integers), must it contain two integers whose ratio is a square?  No one knows.  In the broader context of the disjointness between additive and multiplicative configurations and...

### Measure Growth in Compact Simple Lie Groups

Yifan Jing

The celebrated product theorem says if A is a generating subset of a finite simple group of Lie type G, then |AAA| \gg \min \{ |A|^{1+c}, |G| \}. In this talk, I will show that a similar phenomenon appears in the continuous setting: If A is a subset...

### Deviation Spectrum of Ergodic Integrals for Locally Hamiltonian Flows on Surfaces

Krzysztof Fraczek

The talk will consists of a long historical introduction to  the topic of deviation of ergodic averages for locally Hamiltonian flows on compact surafces  as well as some current results obtained in collaboration with Corinna Ulcigrai  and Minsung...

### Sets with small l^1 Fourier norm

Thomas Bloom

A famous conjecture of Littlewood states that the Fourier transform of every set of N integers has l^1 norm at least log(N), up to a constant multiplicative factor. This was proved independently by McGehee-Pigno-Smith and Konyagin in the 1980s. This...

### Linear equations in smooth numbers

Lilian Matthiesen

A number is called y-smooth if all of its prime factors are bounded above by y. The set of y-smooth numbers below x forms a sparse subset of the integers below x as soon as x is sufficiently large in terms of y. If f_1, …, f_r \in Z[x_1,…,x_s] is a...

### Some small progress on the Mizohata-Takeuchi conjecture

Marina Iliopoulou

The restriction conjecture, one of the most central problems in harmonic analysis, studies the Fourier transform of functions defined on curved surfaces; specifically, it claims that the level sets of such Fourier transforms are relatively small...