Newton Polyhedrons and Hodge Numbers of Non-degenerate Laurent Polynomials

Abstract: Claude Sabbah has defined the Fourier transform $G$ of the Gauss-Manin system for a non-degenerate and convenient Laurent polynomial and has shown that there exists a polarized mixed Hodge structure on the vanishing cycle of $G$. In this article, we consider certain non-degenerate and convenient Laurent polynomials $f_{P,\mathbf{a}}$, whose Newton polyhedron at infinity is a simplicial polytope $P$. First, we consider the stacky fan $\boldsymbol{\Sigma}P$ given by $P$ and show that for each quotient stacky fan of $\boldsymbol{\Sigma}_P$, there is a natural polarized mixed Hodge structure on the ring of conewise polynomial functions on it. Then, we describe the polarized mixed Hodge structure on the vanishing cycle associated to $f{P,\mathbf{a}}$ using these rings of conewise polynomial functions. In particular, we compute the Hodge diamond of the vanishing cycle. As a further consequence, we can solve the Birkhoff problem of such a Laurent polynomial by using elementary methods.