On regular semigroups whose idempotents form a semigroup: Addenda
نویسندگان
چکیده
منابع مشابه
Semigroups whose idempotents form a subsemigroup ∗
We prove that every semigroup S in which the idempotents form a sub-semigroup has an E-unitary cover with the same property. Furthermore, if S is E-dense or orthodox, then its cover can be chosen with the same property. Then we describe the structure of E-unitary dense semigroups. Our results generalize Fountain's results on semigroups in which the idempotents commute, and are analogous to thos...
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Proper extensions that are “injective on L-related idempotents” of R-unipotent semigroups, and much more generally of the class of generalised left restriction semigroups possessing the ample and congruence conditions, referred to here as glrac semigroups, are described as certain subalgebras of a λ-semidirect product of a left regular band by an R-unipotent or by a glrac semigroup, respectivel...
متن کاملPermutative Semigroups Whose Congruences Form a Chain ∗
Semigroups whose congruences form a chain are often termed ∆-semigroups. The commutative ∆-semigroups were determined by Schein and by Tamura. A natural generalization of commutativity is permutativity: a semigroup is permutative if it satisfies a non-identity permutational identity. We completely determine the permutative ∆-semigroups. It turns out that there are only six noncommutative exampl...
متن کاملFinite Abundant Semigroups in Which the Idempotents Form a Subsemigroup*
We consider certain abundant semigroups in which the idempotents form a subsemigroup, and which we call bountiful semigroups. We find a simple criterion for a finite bountiful semigroup to be a member of the join of the pseudovarieties of finite groups and finite aperiodic semigroups.
متن کاملAdjoining Idempotents to Semigroups
Our paper is inspired by the paper [3] by M. Nathanson, in which he considers iteration of the process of adjoining identities or zeros to semigroups and characterizes the resulting semigroup in the case when one starts with the trivial semigroup. We consider also the third type of adjoining, namely, we adjoin idempotents “that behave like some already existing elements.” We investigate the pro...
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ژورنال
عنوان ژورنال: Bulletin of the Australian Mathematical Society
سال: 1970
ISSN: 0004-9727,1755-1633
DOI: 10.1017/s0004972700045950