SEMIGROUP FORUM, vol.65, no.3, pp.329-335, 2002 (SCI-Expanded)
The purpose of this paper is twofold. First we determine some forms of the relations in a finite semigroup presentation with zero, deficiency which does or does not define a group. Moreover, we conclude that a finite Rees matrix semigroup M [G; I, Lambda; P] is efficient when G is efficient and the index sets I, Lambda are finite.