Varieties of finitely approximable semigroups
Sbornik. Mathematics, Tome 17 (1972) no. 3, pp. 349-355
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In this paper we discuss the question of when a variety of commutative or nilpotent semigroups consists only of finitely approximate semigroups. Moreover, we give necessary and sufficient conditions in order to have $\operatorname{Var}S=q\operatorname{Var}S$ (here $\operatorname{Var}S$ denotes the variety generated by the semigroup $S$, and $q\operatorname{Var}S$ the quasivariety generated by $S$). Bibliography: 3 titles.
[1] S. G. Mamikonyan, “Ob approksimatsii polugrupp, udovletvoryayuschikh kommutatornomu usloviyu”, Izv. VUZov, Matematika, 1970, no. 1(92), 70–72
[2] A. Yu. Olshanskii, “Mnogoobraziya finitno-approksimiruemykh grupp”, Izv. AN SSSR, seriya matem., 33 (1969), 915–927
[3] E. S. Lyapin, Polugruppy, Fizmatgiz, Moskva, I960