State Elimination Ordering Strategies: Some Experimental Results

Recently, the problem of obtaining a short regular expression equivalent to a given finite automaton has been intensively investigated. Algorithms for converting finite automata to regular expressions have an exponential blow-up in the worst-case. To overcome this, simple heuristic methods have been proposed. In this paper we analyse some of the heuristics presented in the literature and propose new ones. We also present some experimental comparative results based on uniform random generated deterministic finite automata.Comment: In Proceedings DCFS 2010, arXiv:1008.127

2010): State Elimination Ordering Strategies: Some Experimental Results

Abstract. Recently, the problem of obtaining a short regular expression equivalent to a given finite automaton has been intensively investigated. Algorithms for converting finite automata to regular expressions have an exponential blow-up in the worst-case. To overcome this, simple heuristic methods have been proposed. In this paper we analyse some of the heuristics presented in the literature and propose new ones. We also present some experimental comparative results based on uniform random generated deterministic finite automata

Local Elimination-Strategies in Automata for Shorter Regular Expressions

Abstract. We propose a construction of regular expressions from particularly restricted NFA via extended automata. It proceeds in two main steps, elimination of cycles in the state graph followed by a recursive construction of the final regular expression. Inbetween these eliminations, series-parallel substructures are reduced to single transitions. The process gives rise to compact regular expressions by avoiding redundancies in the intermediate extended automata. Altough derived from state-elimination-techniques, the constructions are rather ’transitionoriented’.