Cyclotomic generating functions, empty weighted complete intersections and positivity

TL;DR

This paper establishes combinatorial conditions ensuring the non-negativity of coefficients in cyclotomic generating functions, extending previous work and solving several open conjectures in algebraic and combinatorial geometry.

Contribution

It introduces new combinatorial criteria for positivity of cyclotomic generating functions, extending prior results and resolving multiple open conjectures.

Findings

Provided sufficient conditions for non-negativity of CGF coefficients

Solved a problem by Billey and Swanson

Proved most cases of conjectures by Stanton, Gatzweiler, and Krattenthaler

Abstract

We give a sufficient combinatorial condition for the non-negativity of the coefficients of polynomial quotients of products of $q$-integers, also known as cyclotomic generating functions (CGFs). This slightly extends work by Iano-Fletcher, Pizzato, Sano and Tasin, who studied this condition as a criterion for quasismoothness of complete intersections in weighted projective spaces. As a consequence, we solve a problem by Billey and Swanson, prove most cases of an unpublished conjecture by Stanton and most cases of two conjectures by Gatzweiler and Krattenthaler. We also study sufficient conditions given by structural properties of the division lattice.