Commutative zeropotent semigroups with few invariant congruences. (English) Zbl 1165.20322

Summary: Commutative semigroups satisfying the equation \(2x+y=2x\) and having only two \(G\)-invariant congruences for an automorphism group \(G\) are considered. Some classes of these semigroups are characterized and some other examples are constructed.


20M14 Commutative semigroups
20M30 Representation of semigroups; actions of semigroups on sets
08A30 Subalgebras, congruence relations
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