×

On semigroup constructions induced by commuting retractions on a set. (English) Zbl 1491.20110

Summary: If \(\mathbf{G}=(G;\cdot)\) is a semigroup, \(I\) is arbitrary set and \(\lambda, \rho :I\rightarrow I\) are mappings satisfying the equalities \(\lambda \lambda =\lambda\), \(\rho\rho =\rho\) and \(\lambda\rho =\rho\lambda\) then we define the semigroup \((G^I,\times)\) where \((x\times y)(i) := x(\lambda i)\cdot y(\rho i)\). This construction gives rise to four covariant and two contravariant functors and constitute three adjoint situations. We apply this functors for finding representation theorems.

MSC:

20M10 General structure theory for semigroups
20M15 Mappings of semigroups
Full Text: DOI

References:

[1] Burris, S., Sankappanavar, H.P.: A Course in Universal Algebra. Springer (1981) · Zbl 0478.08001
[2] Nagy, A.: Special Classes of Semigroups. Springer (2001) · Zbl 0985.20050
[3] Strecker, R., Construction of medial semigroups, Comment. Math. Univ. Carol., 25, 689-697 (1984) · Zbl 0567.20040
[4] Strecker, R.: Konstruktion freier medialer Halbgruppen aus kommutativen Halbgruppen. Wiss. Z. Pädagog. Hochsch. “Liselotte Herrmann” Güstrow. Math.-Naturwiss. Fak. 20, 265-270 (1982) · Zbl 0579.20059
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.