Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-27T08:24:33.894Z Has data issue: false hasContentIssue false

Semigroups with zero whose idempotents form a subsemigroup

Published online by Cambridge University Press:  14 November 2011

Gracinda M. S. Gomes
Affiliation:
Centro de Algebra da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1699 Lisboa, Portugal
John M. Howie
Affiliation:
Mathematical Institute, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9SS, U.K.

Abstract

The structure of a categorical, E*-dense, E*-unitary E-semigroup S is elucidated in terms of a ‘B-quiver’, where B is a primitive inverse semigroup. In the case where S is strongly categorical, B is a Brandt semigroup. A covering theorem is also proved, to the effect that every categorical E*-dense E-semigroup has a cover which is a categorical, E*-dense, E*-unitary E-semigroup.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1Almeida, J., Pin, J.-E. and Weil, P.. Semigroups whose idempotents form a subsemigroup. Math. Proc.Cambridge Philos. Soc. 111 (1992), 241–53.CrossRefGoogle Scholar
2Billhardt, B.. On a wreath product embedding and idempotent pure congruences on inverse semigroups. Semigroup Forum 45 (1992), 4554.CrossRefGoogle Scholar
3Fountain, J.. E-unitary dense covers of E-dense monoids. Bull. London Math. Soc. 22 (1990), 353–8.CrossRefGoogle Scholar
4Fountain, J. and Gomes, G. M. S.. Proper left type-A covers. Portugal. Math. 51 (1994), 305–18.Google Scholar
5Gomes, G. M. S.. A characterization of the group congruences on a semigroup. Semigroup Forum 46 (1993), 4853.CrossRefGoogle Scholar
6Gomes, G. M. S. and Howie, J. M.. A P-theorem for inverse semigroups with zero. Portugal. Math. 53 (1996), 257–78.Google Scholar
7Gomes, G. M. S. and Szendrei, M.. Idempotent-pure extensions of inverse semigroups via quivers. J. Pure Appl. Algebra (to appear).Google Scholar
8Howie, J. M.. Fundamentals of semigroup theory (Oxford: Oxford University Press, 1995).CrossRefGoogle Scholar
9McAllister, D. B.. Groups, semilattices and inverse semigroups. Trans. Amer. Math. Soc. 192 (1974), 227–44.Google Scholar
10McAllister, D. B.. Groups, semilattices and inverse semigroups, II. Trans. Amer. Math. Soc. 196 (1974), 351–70.CrossRefGoogle Scholar
11Margolis, S. W. and Pin, J.-E.. Inverse semigroups and extensions of groups by semilattices. J. Algebra 110 (1987), 277–97.CrossRefGoogle Scholar
12Munn, W. D.. Brandt congruences on inverse semigroups. Proc. London Math. Soc. (3) 14 (1964), 154–64.CrossRefGoogle Scholar
13O'Carroll, L.. Inverse semigroups as extensions of semilattices. Glasgow Math. J. 16 (1975), 1221.CrossRefGoogle Scholar
14Pin, J.-E.. Finite semigroups as categories, ordered semigroups or compact semigroups. In Semigroup Theory and its Applications eds. Hofmann, K. H. and Mislove, M. W., London Mathematical Society Lecture Note Series 231, pp. 107–21 (Cambridge: Cambridge University Press, 1996).CrossRefGoogle Scholar