5 results
Vojtěch Forejt ; Petr Jančar ; Stefan Kiefer ; James Worrell.
We study the bisimilarity problem for probabilistic pushdown automata (pPDA) and subclasses thereof. Our definition of pPDA allows both probabilistic and non-deterministic branching, generalising the classical notion of pushdown automata (without epsilon-transitions). We first show a general […]
Published on November 15, 2018
Antonia Lechner ; Richard Mayr ; Joël Ouaknine ; Amaury Pouly ; James Worrell.
Freeze LTL is a temporal logic with registers that is suitable for specifying properties of data words. In this paper we study the model checking problem for Freeze LTL on one-counter automata. This problem is known to be undecidable in general and PSPACE-complete for the special case of […]
Published on December 7, 2018
Franck van Breugel ; Babita Sharma ; James Worrell.
Desharnais, Gupta, Jagadeesan and Panangaden introduced a family of behavioural pseudometrics for probabilistic transition systems. These pseudometrics are a quantitative analogue of probabilistic bisimilarity. Distance zero captures probabilistic bisimilarity. Each pseudometric has a discount […]
Published on April 9, 2008
Stefan Kiefer ; Ines Marusic ; James Worrell.
We consider the problem of minimising the number of states in a multiplicity tree automaton over the field of rational numbers. We give a minimisation algorithm that runs in polynomial time assuming unit-cost arithmetic. We also show that a polynomial bound in the standard Turing model would require […]
Published on March 28, 2017
Hsi-Ming Ho ; Joël Ouaknine ; James Worrell.
It is known that Metric Temporal Logic (MTL) is strictly less expressive than the Monadic First-Order Logic of Order and Metric (FO[<, +1]) when interpreted over timed words; this remains true even when the time domain is bounded a priori. In this work, we present an extension of MTL with the same […]
Published on May 10, 2019