FINITELY GENERATED SEMIGROUPS WITH SUCH A PRESENTATION THAT ALL THE CONGRUENCE CLASSES ARE CONTEXT-FREE LANGUAGES (Languages, Computations, and Algorithms in Algebraic Systems)
Kunitaka Shoji · Institutional Repositories DataBase (IRDB) · 2009
In this paper, we investigate finitely generated semigroups with such a presentation that all the congruence classes are context-free languages.A monoid $M$ is called finitely generated if there exists a finite set of $X$ and there exists a surjective homomorphism of $X^{*}$ to $M$ which maps an empty word onto the identity element of $M$ .