Solving E (φUψ) using the CEGAR Approach

Petri nets are an established formal method for modelling and verifying asynchronous, concurrent and distributed systems. To verify a specification, given as a temporal logic formula, state space methods often encounter the state space explosion problem. We propose a verification technique to solve the CTL query E (φ U ψ) using the Petri net state equation with a counterexample guided abstraction refinement (CEGAR) approach. The algorithm tries to solve EF ψ, while keeping φ true. Especially in case the property does not hold, the technique often terminates quickly. As a side product we show that (EX)φ formulas can be solved with the CEGAR approach as well.