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Totally commutative semigroups

Published online by Cambridge University Press:  09 April 2009

Józef Dudek
Affiliation:
Institute of Mathematics Wroclaw UniversityP1. Grunwaldzki 2/4 50-384 Wroclaw, Poland
Andrzej Kisielewicz
Affiliation:
Institute of Mathematics Technical University of WroclawWybrzeze Wyspianskiego 27 50-370 Wroclaw, Poland
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Abstract

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A semigroup is totally commutative if each of its essentially binary polynomials is commutative, or equivalently, if in every polynomial (word) every two essential variables commute. In the present paper we describe all varieties (equational classes) of totally commutative semigroups, lattices of subvarieties for any variety, and their free spectra.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1991

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