Conjugation in semigroups

The action of any group on itself by conjugation and the corresponding conjugacy relation play an important role in group theory. There have been several attempts to extend the notion of conjugacy to semigroups. In this paper, we present a new definition of conjugacy that can be applied to an arbitr...

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Detalhes bibliográficos
Autor principal: Araújo, João (author)
Outros Autores: Konieczny, Janusz (author), Malheiro, António (author)
Formato: article
Idioma:eng
Publicado em: 2015
Assuntos:
Texto completo:http://hdl.handle.net/10400.2/3798
País:Portugal
Oai:oai:repositorioaberto.uab.pt:10400.2/3798
Descrição
Resumo:The action of any group on itself by conjugation and the corresponding conjugacy relation play an important role in group theory. There have been several attempts to extend the notion of conjugacy to semigroups. In this paper, we present a new definition of conjugacy that can be applied to an arbitrary semigroup and it does not reduce to the universal relation in semigroups with a zero. We compare the new notion of conjugacy with existing definitions, characterize the conjugacy in various semigroups of transformations on a set, and count the number of conjugacy classes in these semigroups when the set is infinite.