Inhabitation for Non-idempotent Intersection Types

Abstract

The inhabitation problem for intersection types in the lambda-calculus isknown to be undecidable. We study the problem in the case of non-idempotentintersection, considering several type assignment systems, which characterizethe solvable or the strongly normalizing lambda-terms. We prove thedecidability of the inhabitation problem for all the systems considered, byproviding sound and complete inhabitation algorithms for them