2017
Jan
02

# NT&AG: Ehud de Shalit (HUJI), "Geometry modulo p of some unitary Shimura varieties"

2:00pm to 3:00pm

## Location:

Ros Building, 70A

Abstract: This talk will be about joint work with Eyal Goren about the

structure of Picard modular surfaces at a prime p which is inert in the

underlying quadratic imaginary field. The main tool for studying the bad

reduction of Shimura varieties is the theory of local models (due to de

Jong and Rapoport-Zink). Our results concern global geometric questions

which go beyond the theory of global models. For example, we are able to

count supersingular curves on the Picard surface. We also study certain

structure of Picard modular surfaces at a prime p which is inert in the

underlying quadratic imaginary field. The main tool for studying the bad

reduction of Shimura varieties is the theory of local models (due to de

Jong and Rapoport-Zink). Our results concern global geometric questions

which go beyond the theory of global models. For example, we are able to

count supersingular curves on the Picard surface. We also study certain