International Seminar on Automorphic Forms

Salim Tayou (Harvard University)

Kudla-Millson and Borcherds have proved some time ago that the generating series of special divisors in orthogonal Shimura varieties are modular forms. In this talk, I will explain an extension of these results to toroidal compactifications where we prove that the generating series is a mixed mock modular form. More precisely, we find an explicit completion using theta series associated to rays in the cone decomposition. The proof relies on intersection theory at the boundary of the Shimura variety. This recovers and refines recent results of Bruinier and Zemel. The result of this talk are joint work with Philip Engel and Francois Greer.

You can join the Zoom meeting at https://tu-darmstadt.zoom.us/j/68048280736

The password is the first Fourier coefficient of the modular j-function (as digits).