Resolutions of local face modules, functoriality, and vanishing of local $h$-vectors

Matt Larson, Sam Payne, Alan Stapledon

Published 2022-09-08Version 1

We study the local face modules of triangulations of simplices, i.e., the modules over face rings whose Hilbert functions are local $h$-vectors. In particular, we give resolutions of these modules by subcomplexes of Koszul complexes as well as functorial maps between modules induced by inclusions of faces. As applications, we prove a new monotonicity result for local $h$-vectors and new results on the structure of faces in triangulations with vanishing local $h$-vectors.