Reducibility vs. definability for pseudovarieties of semigroups

• Tipo: Artigo em Revista Científica Internacional
• Data: 2016

Autores

Almeida, J (Autor) FCUP; Klima, O (Autor) Outra

Revista

Título: International Journal of Algebra and Computation

Vol. 26

Páginas: 1483-1495

ISSN: 0218-1967

Editora: World Scientific

Indexação

ISI Web of Knowledge - 0 Citações

Scopus - 0 Citações

Outras Informações

ID Authenticus: P-00M-75D

DOI: 10.1142/s0218196716500648

Abstract (EN): It is easy to show that a pseudovariety which is reducible with respect to an implicit signature sigma for the equation x = y can also be defined by sigma-identities. We present several negative examples for the converse using signatures in which the pseudovarieties are usually defined. An ordered example issue from the extended Straubing-Therien hierarchy of regular languages is also shown to provide a positive example for the inequality x <= y.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 13