Series-Parallel Automata and Short Regular Expressions
نویسندگان
چکیده
Computing short regular expressions equivalent to a given finite automaton is a hard task. In this work we present a class of acyclic automata for which it is possible to obtain in time O(n2 log n) an equivalent regular expression of size O(n). A characterisation of this class is made using properties of the underlying digraphs that correspond to the series-parallel digraphs class. Using this characterisation we present an algorithm for the generation of automata of this class and an enumerative formula for the underlying digraphs with a given number of vertices.
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عنوان ژورنال:
- Fundam. Inform.
دوره 91 شماره
صفحات -
تاریخ انتشار 2009