Relating timed and register automata

Diego Figueira
(INRIA, ENS Cachan, LSV, France)
Piotr Hofman
(Institute of Informatics, University of Warsaw, Poland)
Sławomir Lasota
(Institute of Informatics, University of Warsaw, Poland)

Timed automata and register automata are well-known models of computation over timed and data words respectively. The former has clocks that allow to test the lapse of time between two events, whilst the latter includes registers that can store data values for later comparison. Although these two models behave in appearance differently, several decision problems have the same (un)decidability and complexity results for both models. As a prominent example, emptiness is decidable for alternating automata with one clock or register, both with non-primitive recursive complexity. This is not by chance.

This work confirms that there is indeed a tight relationship between the two models. We show that a run of a timed automaton can be simulated by a register automaton, and conversely that a run of a register automaton can be simulated by a timed automaton. Our results allow to transfer complexity and decidability results back and forth between these two kinds of models. We justify the usefulness of these reductions by obtaining new results on register automata.

In Sibylle Fröschle and Frank D. Valencia: Proceedings 17th International Workshop on Expressiveness in Concurrency (EXPRESS'10), Paris, France, August 30th, 2010, Electronic Proceedings in Theoretical Computer Science 41, pp. 61–75.
Published: 28th November 2010.

ArXived at: bibtex PDF

Comments and questions to:
For website issues: