Abstract
It has been known for a long time that every finite orthodox completely regular semigroup has a finite basis of identities, and that every finite central completely simple semigroup has a finite basis of identities. In the present paper, a common generalization of these two facts is established. It is shown that every finite central locally orthodox completely regular semigroup has a finite basis of identities. The proof of this latter fact which is presented in this paper employs significantly the celebrated theorem of Libor Polák on the structure of the lattice of all varieties of completely regular semigroups.
Similar content being viewed by others
References
Fitz-Gerald, D.G.: On inverses of products of idempotents in regular semigroups. J. Aust. Math. Soc. 13, 335–337 (1972). https://doi.org/10.1017/S1446788700013756
Jones, P.R.: On the lattice of varieties of completely regular semigroups. J. Aust. Math. Soc. Ser. A 35, 227–235 (1983). https://doi.org/10.1017/S1446788700025726
Kad’ourek, J.: Uncountably many varieties of completely simple semigroups with metabelian subgroups. Glasg. Math. J. 48, 365–410 (2006). https://doi.org/10.1017/S0017089506003132
Kad’ourek, J.: On finite completely simple semigroups having no finite basis of identities. Semigroup Forum 97, 154–161 (2018). https://doi.org/10.1007/s00233-017-9907-0
Neumann, H.: Varieties of Groups. Springer, New York (1967)
Oates, S., Powell, M.B.: Identical relations in finite groups. J. Algebra 1, 11–39 (1964). https://doi.org/10.1016/0021-8693(64)90004-3
Pastijn, F.J.: The lattice of completely regular semigroup varieties. J. Aust. Math. Soc. Ser. A 49, 24–42 (1990). https://doi.org/10.1017/S1446788700030214
Pastijn, F.J., Petrich, M.: Congruences on regular semigroups. Trans. Am. Math. Soc. 295, 607–633 (1986). https://doi.org/10.2307/2000054
Pastijn, F.J., Trotter, P.G.: Lattices of completely regular semigroup varieties. Pac. J. Math. 119, 191–214 (1985). https://doi.org/10.2140/pjm.1985.119.191
Petrich, M., Reilly, N.R.: Near varieties of idempotent generated completely simple semigroups. Algebra Universalis 16, 83–104 (1983). https://doi.org/10.1007/BF01191755
Petrich, M., Reilly, N.R.: All varieties of central completely simple semigroups. Trans. Am. Math. Soc. 280, 623–636 (1983). https://doi.org/10.2307/1999637
Petrich, M., Reilly, N.R.: Completely Regular Semigroups. Wiley, New York (1999)
Polák, L.: On varieties of completely regular semigroups I. Semigroup Forum 32, 97–123 (1985). https://doi.org/10.1007/BF02575527
Polák, L.: On varieties of completely regular semigroups II. Semigroup Forum 36, 253–284 (1987). https://doi.org/10.1007/BF02575021
Polák, L.: On varieties of completely regular semigroups III. Semigroup Forum 37, 1–30 (1988). https://doi.org/10.1007/BF02573119
Rasin, V.V.: Varieties of orthodox Clifford semigroups. Izv. Vyssh. Uchebn. Zaved. Mat. 1982(11), 82–85 (1982). (in Russian)
Reilly, N.R.: Varieties of completely regular semigroups. J. Aust. Math. Soc. Ser. A 38, 372–393 (1985). https://doi.org/10.1017/S144678870002365X
Reilly, N.R.: Completely regular semigroups. In: Lattices. Semigroups, and Universal Algebra, Proceedings of the International Conference held at the University of Lisbon, Lisbon, 1988, pp. 225–242. Plenum Press, New York (1990)
Shevrin, L.N., Volkov, M.V.: Identities of semigroups. Izv. Vyssh. Uchebn. Zaved. Mat. 1985(11), 3–47 (1985). (in Russian)
Trotter, P.G.: Subdirect decompositions of the lattice of varieties of completely regular semigroups. Bull. Aust. Math. Soc. 39, 343–351 (1989). https://doi.org/10.1017/S0004972700003269
Acknowledgements
This research has been supported by the Grant Agency of the Czech Republic under the Project GA19-12790S.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Marcel Jackson.
Dedicated to the memory of Libor Polák.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Kad’ourek, J. On bases of identities of finite central locally orthodox completely regular semigroups. Semigroup Forum 102, 697–724 (2021). https://doi.org/10.1007/s00233-021-10174-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00233-021-10174-1