Convex bodies and asymptotic invariants for powers of monomial ideals

Abstract

Continuing a well established tradition of associating convex bodies to monomial ideals, we initiate a program to construct asymptotic Newton polyhedra from decompositions of monomial ideals. This is achieved by forming a graded family of ideals based on a given decomposition. We term these graded families powers since they generalize the notions of ordinary and symbolic powers. We introduce a novel family of irreducible powers.Irreducible powers and symbolic powers of monomial ideals are studied by means of the corresponding irreducible polyhedron and symbolic polyhedron respectively. Asymptotic invariants for these graded families are expressed as solutions to linear optimization problems on the respective convex bodies. This allows to establish a lower bound on the Waldschmidt constant of a monomial ideal, an asymptotic invariant which can be defined using the symbolic polyhedron, by means of an analogous invariant stemming from the irreducible polyhedron, which we introduce under the name of naive Waldschmidt constant.