Checking Reachability Properties for Timed Automata via SAT

Abstract

The paper deals with the problem of checking reachability for timed automata. The main idea consists in combining the well-know forward reachability algorithm and the Bounded Model Checking (BMC) method. In order to check reachability of a state satisfying some desired property, first the transition relation of a timed automaton is unfolded iteratively to some depth and encoded as a propositional formula. Next, the desired property is translated to a propositional formula and the satisfiability of the conjunction of the two defined above formulas is checked. The unfolding of the transition relation can be terminated when either a state satisfying the property has been found or all the states of the timed automaton have been searched. The efficiency of the method is strongly supported by the experimental results.