Title: Interpolation sets and arithmetic progressions
Abstract: Given a set S of positive measure on the unit circle, a set of integers K is an interpolation set (IS) for S if for any data {c(k)} in l^2(K) there exists a function f in L^2(S) such that its Fourier coefficients satisfy f^(k)=c(k) for all k in K.
In the talk I will discuss the relationship between the concept of IS and the existence arithmetic structure in the set K, I will focus primarily on the case where K contains arbitrarily long arithmetic progressions with specified lengths and step sizes.
Title: An improved bound for Hadwiger’s covering problem via thin shell inequalities for the convolution square. Abstract: A long-standing open problem, known as Hadwiger’s covering problem, asks what is the smallest natural number N(n) such that every convex body in {\mathbb R}^n can be covered by a union of the interiors of at most N(n) of its translates. Despite continuous efforts, the best-known general upper bound for this number remain as it was more than half a decade ago, and is of the order of \binom{2n}{n}n\ln n.
Title: Szego theorem for measures on the real line: optimal results and
applications.
Abstract: Measures on the unit circle for which the logarithmic integral
converges can be characterized in many different ways: e.g., through
their Schur parameters or through the predictability of the future from
the past in Gaussian stationary stochastic process. In this talk, we
consider measures on the real line for which logarithmic integral exists
and give their complete characterization in terms of the Hamiltonian in
De Branges canonical system. This provides a generalization of the
Title: On a local version of the fifth Busemann-Petty Problem
Abstract:
In 1956, Busemann and Petty posed a series of questions about symmetric convex bodies, of which only the first one has been solved. Their fifth problem asks the following.
Let K be an origin symmetric convex body in the n-dimensional Euclidean space and let H_x be a hyperplane passing through the origin orthogonal to a unit direction x. Consider a hyperplane G parallel to H_x and supporting to K and let
C(K,x)=vol(K\cap H_x)dist (0, G).
