Proving Correctness of Logically Decorated Graph Rewriting Systems

Abstract

We first introduce the notion of logically decorated rewriting systems where the left-hand sides are endowed with logical formulas which help to express positive as well as negative application conditions, in addition to classical pattern-matching. These systems are defined using graph structures and an extension of combinatory propositional dynamic logic, CPDL, with restricted universal programs, called C2PDL. In a second step, we tackle the problem of proving the correctness of logically decorated graph rewriting systems by using a Hoare-like calculus. We introduce a notion of specification defined as a tuple (Pre, Post, R, S) with Pre and Post being formulas of C2PDL, R a rewriting system and S a rewriting strategy. We provide a sound calculus which infers proof obligations of the considered specifications and establish the decidability of the verification problem of the (partial) correctness of the considered specifications.