Bounded Verification of Past LTL

Abstract

Temporal logics with past operators are gaining increasing importance in several areas of formal verification for their ability to concisely express useful properties. In this paper we propose a new approach to bounded verification of PLTL, the linear time temporal logic extended with past temporal operators. Our approach is based on the transformation of PLTL into Separated Normal Form, which in turn is amenable for reduction to propositional satisfiability. An experimental evaluation shows that our approach induces encodings which are significantly smaller and more easily solved than previous approaches, in the cases of both model checking and satisfiability problems.