Extensions of algebraic systems

Awad A. Iskander
1984 Transactions of the American Mathematical Society  
There are several generalizations to universal algebras of the notion "The group 31 is an extension of the group ii by the group G ". In this paper we study three such generalizations and the corresponding products of classes of algebraicsystems. Various results are presented. One such theorem characterizes the weakly congruence regular varieties admitting extensions of a particular sort. Another result gives, under a weak congruence permutability condition, an equational basis for the variety
more » ... btained by applying one such product to two other varieties. 21/0(21,33') = 6.
doi:10.1090/s0002-9947-1984-0719672-2 fatcat:wrlaywqdhjd2njur33iklpmrgy