Callum Barber

most citedSemigroup Congruences and Subsemigroups of the Direct Square

1 citations · 1 across the 2 of their papers we have counts for

collaborators

2 papers

math.RA2026

Comparing Numbers of Diagonal Subsemigroups and Congruences for Semigroups

Callum Barber, Nik Ruškuc

Given a semigroup $S$ , a diagonal subsemigroup $ρ$ is defined to be a reflexive and compatible relation on $S$ , i.e. a subsemigroup of the direct square $S \times S$ containing the…

math.RA2025★ 1 cited

Semigroup Congruences and Subsemigroups of the Direct Square

Callum Barber, Nik Ruškuc

We investigate semigroups $S$ which have the property that every subsemigroup of $S \times S$ which contains the diagonal ${(s, s) : s \in S}$ is necessarily a congruence on $S…