Algebraic automata and context-free sets

The concepts of "equational≓ and "recognizable≓ are defined for sets of elements of an arbitrary abstract algebra. Context-free languages and finite-state languages become realizations of the same general concept (of equational sets) when the proper algebra is specified. A principal objective of the paper is to establish in the context of abstract algebra, relationships between such concepts as equational and recognizable sets. © 1968 Academic Press Inc.