Time-Action Alternating Model for Timed LOTOS and its Symbolic Verification of Bisimulation Equivalence

Veriication of timed bisimulation equivalence is generally diicult because of state explosion caused by concrete time values. In this paper, we propose a veriication method to verify timed bisimulation equivalence of two timed processes using a symbolic technique similar to (Hennessy and Lin 1995). We rst propose a new model of timed processes, Alternating Timed Symbolic Labelled Transition System(A-TSLTS). In A-TSLTS, each state has some parameter variables and those values determine its behaviour. Each transition in an A-TSLTS has a guard predicate. The transition is executable if and only if its guard predicate is true under speciied parameter values. In the proposed method, we can obtain the weakest condition for a state-pair in a nite A-TSLTS to make the state-pair be timed bisimulation equivalent. We also show that this result can be applied to the language LOTOS/T(Nakata et al. 1994), a timed extension of LOTOS(ISO 1989).