Timed Systems in SAL

The Symbolic Analysis Laboratory (SAL) is a set of tools for the specification, exploration, and verification of state-transition systems. SAL includes symbolic model-checking tools based on solvers and decision procedures for linear arithmetic, uninterpreted functions, and propositional logic, among others. This enables the analysis of a variety of infinite-state systems. In particular, SAL can be used to model and verify timed systems, which combine real-valued and discrete state variables. This document reports on several examples and experiments in modeling and verification of timed system in SAL. Different specification approaches are presented and compared, from a direct encoding of traditional timed automata to a novel modeling method based on event calendars. We present verification techniques that rely on induction and abstraction, and show how these techniques are efficiently supported by the SAL symbolic model-checking tools.