Multi-Core Emptiness Checking of Timed Büchi Automata using Inclusion Abstraction

This paper contributes to the multi-core model checking of timed automata (TA) with respect to liveness properties, by investigating checking of TA Büchi emptiness under the very coarse inclusion abstraction or zone subsumption, an open problem in this field.We show that in general Büchi emptiness is not preserved under this abstraction, but some other structural properties are preserved. Based on those, we propose a variation of the classical nested depth-first search (NDFS) algorithm that exploits subsumption. In addition, we extend the multi-core cndfs algorithm with subsumption, providing the first parallel LTL model checking algorithm for timed automata.The algorithms are implemented in LTSmin, and experimental evaluations show the effectiveness and scalability of both contributions: subsumption halves the number of states in the real-world FDDI case study, and the multi-core algorithm yields speedups of up to 40 using 48 cores