Series-Parallel Automata and Short Regular Expressions (2009)
by
Nelma Moreira
,
Rogério Reis
BibTeX
@MISC{Moreira09series-parallelautomata,
author = {Nelma Moreira and Rogério Reis},
title = { Series-Parallel Automata and Short Regular Expressions},
year = {2009}
}
Bookmark
 |
 |
 |
 |
 |
 |
OpenURL
Abstract
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.
