Thin polytopes: Lattice polytopes with vanishing local $h^{\ast }$-polynomial

Abstract

In this paper we study the novel notion of thin polytopes: lattice polytopes whose local $h^{\ast }$-polynomials vanish. The local $h^{\ast }$-polynomial is an important invariant in modern Ehrhart theory. Its definition goes back to Stanley with fundamental results achieved by Karu, Borisov & Mavlyutov, Schepers, and Katz & Stapledon. The study of thin simplices was originally proposed by Gelfand, Kapranov and Zelevinsky, where in this case the local $h^{\ast }$-polynomial simply equals its so-called box polynomial. Our main results are the complete classification of thin polytopes up to dimension 3 and the characterization of thinness for Gorenstein polytopes. The paper also includes an introduction to the local $h^{\ast }$-polynomial with a survey of previous results.

32 pages; added monotonicity of local h* (Cor. 2.22), small corrections, generalizations and improvements in the presentation