Shuffle on positive varieties of languages

Autor: Jean-Eric Pin, Antonio Cano Gómez
Přispěvatelé: Departamento de Sistemas Informáticos y Computación [Valencia], Universitat Politècnica de València (UPV), Laboratoire d'informatique Algorithmique : Fondements et Applications (LIAFA), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pin, Jean-Eric
Jazyk: angličtina
Předmět:
Zdroj: Theoretical Computer Science
Theoretical Computer Science, Elsevier, 2004, 312, pp.433-461
ISSN: 0304-3975
1879-2294
DOI: 10.1016/j.tcs.2003.10.034
Popis: We show there is a unique maximal positive variety of languages which does not contain the language (ab)*. This variety is the unique maximal positive variety satisfying the two following conditions: it is strictly included in the class of rational languages and is closed under the shuffle operation. It is also the unique maximal proper positive variety closed under length preserving morphims. The ordered monoids of the corresponding variety of ordered monoids are characterized as follows: for every pair (a, b) of mutually inverse elements, and for every element z of the minimal ideal of the submonoid generated by a and b, (abzab)^ω ≤ ab. In particular this variety is decidable.
Databáze: OpenAIRE