Bands of E-Inversive Unipotent Semigroups
Roman S. Gigoń · Bulletin of the Malaysian Mathematical Sciences Society · 2019
Abstract We study some special types of bands ofE-inversive unipotent semigroups. It has been proved that in anyR-semigroupS, which is a band ofE-inversive unipotent semigroups, the set of its regular elements is a retract ofS. Also, some characterizations ofE-inversive rectangular bands of unipotent semigroups are given. This theorem extends nearly 40-old results from the theory of epigroups. In fact, a more general result is valid in some special subclass of the class ofE-inversive semigroups; this result seems to be (partially) new for all epigroups.