Closed and saturated varieties of semigroups
Shabir Ahmad Ahanger, Muneer Nabi, Aftab Hussain Shah · Communications in Algebra · 2022
We show that all subvarieties of the variety of rectangular bands are closed in the variety of all bands. Further, we show that the variety of regular bands is closed. Next, we introduce the varieties of generalized left [right] regular semigroups and show that all such varieties are saturated and, subsequently, epis from generalized left [right] regular semigroups are surjective.