Ignacio Barros (Universiteit Antwerpen) : Divisors on moduli spaces of K3 surfaces

I will discuss various aspects of the divisor geometry of moduli spaces of K3 surfaces. How they are governed by theta series and Fourier coefficients of modular forms. We provide a finite generating set of Noether-Lefschetz divisors, bounds for the rank of tautological rings, and a formula for the Hodge class in terms of NL divisors. This is based on joint work with Shi He and Paul Kiefer.