Keränen, Veikko On the k-freeness of morphisms on free monoids. (English) Zbl 0604.20056 Ann. Acad. Sci. Fenn., Ser. A I, Diss. 61, 55 p. (1986). A morphism \(h: X\to Y\) between two finitely generated free monoids is k- free if it maps X(k) into Y(k), where \(X(k)=X\setminus X\{w^ k:\) w in \(X\setminus 1\}X\). The author gives necessary conditions for a morphism to be k-free and a finite test to determine whether a morphism h is k- free when it is length uniform from X generated by two symbols. Reviewer: T.J.Harju Cited in 8 Documents MSC: 20M05 Free semigroups, generators and relations, word problems 20M35 Semigroups in automata theory, linguistics, etc. 20M15 Mappings of semigroups Keywords:square free words; repetition free morphisms; DOL systems; finitely generated free monoids PDFBibTeX XMLCite \textit{V. Keränen}, Ann. Acad. Sci. Fenn., Ser. A I, Diss. 61, 55 p. (1986; Zbl 0604.20056)