Subtyping in Logical Form

By using intersection types and filter models we formulate a theory of types for a λ-calculus with record subtyping via a finitary programming logic. Types are interpreted as spaces of filters over a subset of the language of properties (the intersection types) which describes the underlying type free realizability structure. We show that such an interpretation is a PER semantics, proving that the quotient space arising from “logical” PERs taken with the intrinsic ordering is isomorphic to the filter semantics of types.