A game approach to determinize timed automata

International audienceTimed automata are frequently used to model real-time systems. Their determinization is a key issue for several validation problems. However, not all timed automata can be determinized, and determinizability itself is undecidable. In this paper, we propose a game-based algorithm which, given a timed automaton, tries to produce a language-equivalent deterministic timed automaton, otherwise a deterministic over-approximation. Our method generalizes two recent contributions: the determinization procedure of Baier et al. (Proceedings of the 36th international colloquium on automata, languages and programming (ICALP'09), 2009) and the approximation algorithm of Krichen and Tripakis (Form Methods Syst Des 34(3):238–304, 2009). Moreover, we extend it to apply to timed automata with invariants and ε-transitions, and also consider other useful approximations: under-approximation, and combination of under- and over-approximations