### Mathematics Colloquium

** Sam Payne
**

University of Texas at Austin

**Title:** Point counting over finite fields and the cohomology of moduli spaces of curves

**Date:** Friday November 17, 2023

**Place and Time:** Love 101, 3:05-3:55 pm

**Abstract.**
Algebraic geometry studies solution sets of polynomial equations. For instance, over the complex numbers, one may examine the topology of the solution set, whereas over a finite field, one may count its points. For polynomials with integer coefficients, these two fundamental invariants are intimately related via cohomological comparison theorems and trace formulas for the action of Frobenius. I will present recent results regarding point counts over finite fields and the cohomology of moduli spaces of curves that resolve longstanding questions in algebraic geometry and confirm more recent predictions from the Langlands program.