Talk

Lagarias and Rhoades introduced a new class called polyharmonic Maass forms, which are a generalization of harmonic Maass forms. They gave a standard basis for the space of such forms by means of the higher Laurent coefficients of real analytic Eisenstein series. In this talk, we consider a large space of polyharmonic weak Maass forms of integral or half-integral weight, and construct a basis for this space. Furthermore, as an analogue of Zagier’s work on traces of singular moduli, we express the Fourier coefficients in terms of traces of CM-values and cycle integrals.

We prove that under mild restrictions on the Lie algebra $q$ having a polynomial ring of symmetric invariants, the truncated current algebras of $q$ also have a polynomial ring of symmetric invariants.

We consider equations of the form w(x,y)=g where w
is a group word in two letters (= an element of the free
group on two generators), g is a fixed element of a fixed
group G, and solutions are sought among pairs of elements
of G. Our focus is on the case where G is a simple linear
algebraic group. In this talk we consider the case
G=SL(2,K) where K is a number field. We discuss approximation
properties of the corresponding algebraic K-variety.

A meander is a topological configuration of a line and a simple closed curve in the plane (or a pair of simple closed curves on the 2-sphere) intersecting transversely. In physics, meanders provide a model of polymer folding, and their enumeration is directly related to the entropy of the associated dynamical systems.

In 1966, M. Kac published his seminal article ''Can one hear the shape of a drum?'', which deals with the so-called inverse spectral problem: to determine geometric information from spectral data.