An embedding of Timed Transition Systems in HOL

The theory of Timed Transition Systems developed by Henzinger, Manna, and Pnueli provides a formal framework for specifying and reasoning about real-time systems. In this paper, we report on some preliminary investigations into the mechanization of this theory using the HOL theorem prover.We review the main ideas of the theory and describe how it has been formally embedded in HOL. A graphical notation of timed transition diagrams and a real-time temporal logic for requirements have also been embedded in HOL using the embedding of timed transition systems. The proof rules proposed by Henzinger et al have been verified formally and we illustrate their use, as well as some problems we have encountered, by reference to a small example. More work is required on interfaces and proof methods to have a generally usable system.