Polynomial identities and growth functions
A central polynomial of an algebra A is a polynomial f in non-commutative variables that takes central values when evaluated in A. In case it vanishes in A, f is called a polynomial identities of A, otherwise f is a proper central polynomial of A.
The purpose of this talk is to survey some old and new results on the growth of the spaces of central polynomials, proper central polynomials and polynomial identities of an algebra over a field of characteristic zero.

Modular curves are moduli spaces of central importance in arithmetic geometry. In this talk, I will introduce these geometric objects and present some number theoretic results whose proofs used them in an essential way.
After discussing various characterisations and examples, I will explain a comultiplication on these algebras.
a A is representation finite provided there are only finitely many non-isomorphic indecomposable finitely generated A-modules.