Abstract
We show that all subvarieties of left regular bands are closed in the variety of all bands. We also show that all subvarieties of left seminormal bands are saturated in the variety of all bands which shows that, in the category of all bands, any epi from a left seminormal band is surjective.
Similar content being viewed by others
References
Alam, N., Khan, N.M.: Special semigroup amalgamation of quasiunitary subsemigroups and of quasi normal bands. Asian Eur. J. Math. 6, 7 (2013)
Alam, N., Khan, N.M.: Epimorphism, closed and supersaturated semigroups. Commun. Algebra 42, 3137–3146 (2014)
Alam, N., Khan, N.M.: On closed and supersaturated semigroups. Malays. J. Math. 9(3), 409–416 (2015)
Clifford, A.H., Preston, G.B.: The Algebraic Theory of Semigroups. In: Mathematical Surveys and Monographs, vol. 7, No. 1. American Mathematical Society (1961, 1967)
Higgins, P.M.: Saturated and epimorphically closed varieties of semigroups. J. Aust. Math. Soc. 36(2), 153–175 (1984)
Higgins, P.M.: Techniques of Semigroup Theory. Oxford University Press, Oxford (1992)
Howie, J.M.: Fundamentals of Semigroup Theory. Clarendon Press, Oxford (1995)
Isbell, J.R.: Epimorphisms and dominions. In: Proceedings of the Conference on Categorical Algebra, La Jolla, 1965, pp. 232–246. Lange and Springer, Berlin (1966)
Khan, N.M.: On saturated permutative varieties and consequences of permutation identities. J. Aust. Math. Soc. (Ser. A) 38, 186–197 (1985)
Petrich, M.: Lectures in Semigroups. Wiley, New York (1977)
Scheiblich, H.E.: On epis and domonions of bands. Semigroup Forum 13, 103–114 (1976)
Trotter, P.G.: A non surjective epimorphism of bands. Algebra Univers. 22, 109–116 (1986)
Acknowledgements
We sincerely thank the learned referee for his constructive, but critical suggestions that helped us to improve the presentation of the paper. The second author acknowledges the financial support from Science and Engineering Research Board, Govt. of India under the Extra Meural Reseach Grant EMR/2016/007168.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Mark V. Lawson.
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
Ahanger, S.A., Shah, A.H. Epimorphisms, dominions and varieties of bands. Semigroup Forum 100, 641–650 (2020). https://doi.org/10.1007/s00233-019-10047-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00233-019-10047-8