Congruences of maximum regular subsemigroups of variants of finite full transformation semigroups

Igor Dolinka, James East, Nik Ruškuc

Let $T_X$ be the full transformation monoid over a finite set $X$, and fix some $a\in T_X$ of rank $r$. The variant $T_X^a$ has underlying set $T_X$, and operation $f\star g=fag$.…