Abstract (EN):
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 (n(2) 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.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Contacto:
nam@ncc.up.pt; rvr@ncc.up.pt
Nº de páginas:
19