principles and pragmatics of subtyping in PVS

摘要

PVS (Prototype Verification System) is a mechanized framework for formal specification and interactive proof development. The PVS specification language is based on higher-order logic enriched with features such as predicate subtypes, dependent types, recursive data-types, and parametric theories. Subtyping is a central concept in the PVS type system. PVS admits the definition of subtypes corresponding to nonzero integers, prime numbers, injective maps, order-preserving maps, and even empty subtypes. We examine the principles underlying the PVS subtype mechanism and its implementation and use.