Point counting and Galois bounds


Gal Binyamini, Weizmann Institute of Science. 9 décembre 2021 16:00 geo
Abstract:

I'll describe some recent advances in the area of point-counting: that is, results establishing upper bounds on the number of algebraic points of given height and degree in a (usually transcendental) set. I'll explain how, following an idea of Schmidt, these results can be used to deduce lower bounds for the Galois degrees of special points in some arithmetic situations. After reviewing some more classical contexts, I'll discuss how this strategy is applied (in a joint work with Schmidt and Yafaev) to obtain Galois lower bounds for special points in general Shimura varieties (where the more classical abelian methods do not seem to apply) conditional on suitable height bounds. In particular, Andre-Oort is shown to follow from these conjectural height bounds. Very recently, Pila-Shankar-Tsimerman proved these height bounds, thus finishing the proof of general Andre-Oort.