On irregular binomial D-modules

Abstract

We prove that a holonomic binomial D–module MA(I, β) is regular if and only if certain associated primes of I determined by the parameter vector β ∈ Cd are homogeneous. We further describe the slopes of MA(I, β) along a coordinate subspace in terms of the known slopes of some related hypergeometric D–modules that also depend on β. When the parameter β is generic, we also compute the dimension of the generic stalk of the irregularity of MA(I, β) along a coordinate hyperplane and provide some remarks about the construction of its Gevrey solutions.