The Trace Formula for BunG(X)

Abstract

This chapter aims to prove Theorem 1.4.4.1, which is formulated as follows: Theorem 5.0.0.3, let X be an algebraic curve over F q and let G be a smooth affine group scheme over X. Suppose that the fibers of G are connected and that the generic fiber of G is semisimple. Then the moduli stack BunG(X) satisfies the Grothendieck–Lefschetz trace formula. However, Theorem 5.0.0.3 cannot be deduced directly from the Grothendieck–Lefschetz trace formula for global quotient stacks because the moduli stack BunG(X) is usually not quasi-compact. The strategy instead will be to decompose BunG (X) into locally closed substacks BunG(X)[P,ν‎] which are more directly amenable to analysis.