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.
Mezei, J., & Wright, J. B. (1967). Algebraic automata and context-free sets. Information and Control, 11(1–2), 3–29. https://doi.org/10.1016/S0019-9958(67)90353-1