Minimizing Automata on Infinite Words

Abstract

Buchi automata (non-deterministic automata on infinite words with a simple acceptance condition) play a central role in model checking when properties are specified in temporal logic and state spaces are represented explicitly. Model checking then amounts to a graph search in a product of a transition system with a Buchi automaton that represents the specification. From a practical perspective it is therefore important to have procedures at hand which minimize the automata involved if possible. As computing–even approximating–minimum-state automata is PSPACE-hard, heuristics are applied. In the talk, a technique that is frequently used in current heuristics is presented: state-space reductions via simulation relations.