Abstract
Generalizing a property of the pseudovariety of all aperiodic semigroups observed by Tilson, we call E -local a pseudovariety V which satisfies the following property: for a finite semigroup, the subsemigroup generated by its idempotents belongs to V if and only if so do the subsemigroups generated by the idempotents in each of its regular \(\mathcal{D}\)-classes. In this paper, we present several sufficient or necessary conditions for a pseudovariety to be E-local or for a pseudoidentity to define an E-local pseudovariety. We also determine several examples of the smallest E-local pseudovariety containing a given pseudovariety.
Similar content being viewed by others
References
Almeida, J.: Finite Semigroups and Universal Algebra. World Scientific, Singapore (1994). English translation
Almeida, J., Moura, A.: Idempotent-generated semigroups and pseudovarieties. Proc. Edinb. Math. Soc. 54, 545–568 (2011)
Almeida, J., Volkov, M.V.: Profinite identities for finite semigroups whose subgroups belong to a given pseudovariety. J. Algebra Appl. 2, 137–163 (2003)
Fitz-Gerald, D.G.: On inverses of products of idempotents in regular semigroups. J. Aust. Math. Soc. 13, 335–337 (1972)
Graham, R.: On finite 0-simple semigroups and graph theory. Math. Syst. Theory 2, 325–339 (1968)
Pin, J.-E.: Varieties of Formal Languages. Plenum, London (1986). English translation
Pin, J.-E.: PG=BG, a success story. In: Fountain, J. (ed.) NATO Advanced Study Institute Semigroups, Formal Languages and Groups, pp. 33–47. Kluwer Academic, Dordrecht (1995)
Reiterman, J.: The Birkhoff theorem for finite algebras. Algebra Univers. 14, 1–10 (1982)
Rhodes, J., Steinberg, B.: The q-Theory of Finite Semigroups. Springer, New York (2009)
Tilson, B.: Complexity of two J-class semigroups. Adv. Math. 11, 215–237 (1973)
Acknowledgements
The author is grateful to the anonymous referee for warning a flaw in the proof of the initially statement of Theorem 3.11. This work is part of the author’s doctoral thesis, written under the supervision of Prof. Jorge Almeida, from whose advice the author has greatly benefited. This work was supported by Fundação para a Ciência e a Tecnologia (FCT) through the PhD Grant SFRH/BD/19720/2004, through the Centro de Matemática da Universidade do Porto (CMUP) and also through the project PTDC/MAT/65481/2006, which is partly funded by the European Community Fund FEDER.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Jean-Eric Pin.
Rights and permissions
About this article
Cite this article
Moura, A. E-local pseudovarieties. Semigroup Forum 85, 169–181 (2012). https://doi.org/10.1007/s00233-012-9413-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00233-012-9413-3