%A Flavio Corradini
%A Rocco De Nicola
%A Anna Labella
%K     Semantics;
    regular expressions;
    axiomatizations;
    bisimulation.
%L eprints344
%D 1999
%X An alternative (tree-based) semantics for a class of regular expressions is proposed that assigns a central r?le to the + operator and thus to nondeterminism and nondeterministic choice. For the new semantics a consistent and complete axiomatization is obtained from the original axiomatization of regular expressions by Salomaa and by Kozen by dropping the idempotence law for + and the distribution law of ? over +. 
%R 10.1051/ita:1999127
%N 4/5
%J RAIRO - Theoretical Informatics and Applications
%T A finite axiomatization of nondeterministic regular expressions
%P 447-466
%O Mathematics Subject Classification:

    68Q55;
    68Q68;
    08B05
%I Cambridge University Press
%V 33