Koganov, L. M. Remarks concerning the work on Möbius functions and Frobenius constants for a certain class of semigroups. (Russian) Zbl 0791.20073 Studies on semigroups, Interuniv. Collect. Sci. Works, Leningrad, 40-45 (1990). [For the entire collection see Zbl 0714.00010.]The present article contains a supplement to the author’s earlier works [in: “Algebraic systems with one operation and relation”, Interuniv. Collect. Sci. Works, Leningrad 1985, 46-53 (1985; Zbl 0615.10004); “Semigroups and partial groupoids”, Interuniv. Collect. Sci. Works, Leningrad 1987, 15-25 (1987; Zbl 0675.20053)], in the light of facts, which became known to the author after publication of these works. Knowledge of the second of these articles is necessary for reading the present article. MSC: 20M15 Mappings of semigroups 20M05 Free semigroups, generators and relations, word problems 11A25 Arithmetic functions; related numbers; inversion formulas Citations:Zbl 0714.00010; Zbl 0615.10004; Zbl 0675.20053 PDFBibTeX XMLCite \textit{L. M. Koganov}, in: Periodicity and finite generation of the Hom-functor in the category of commutative regular semigroups. . 40--45 (1990; Zbl 0791.20073)