Counting lattice points in compactified moduli spaces of curves

Abstract

We define and count lattice points in the moduli space of stable genus g curves with n labeled points. This extends a construction of the second author for the uncompactified moduli space. The enumeration produces polynomials with top degree coefficients tautological intersection numbers on the compactified moduli space and constant term the orbifold Euler characteristic of the compactified moduli space. We also prove a recursive formula which can be used to effectively calculate these polynomials.