Abstract
It is shown that a formula that was independently obtained earlier for the number of cyclically irreducible words of length n in a symmetric alphabet of a finitely generated free group of rank k and the Whitney formula for a chromatic polynomial of a simple nonself-intersecting cycle of length n with a variable λ are mutually deducible from one another when λ = 2k. The necessary bijections differ for even and odd values of n.
Similar content being viewed by others
References
L. M. Koganov, “Number of cyclically irreducible words in the alphabet of a free group,” in: O. B. Lupanov (ed.), Abstracts of the XIIIth Intern. Conf. on Problems of Theor. Cybernetics, Izd-vo Tsentra Prikl. Issled., Mekh.-Mat. Fak. MGU, Moscow (2002), p. 85.
L. M. Koganov, “Two deductions of an explicit closed expression for the number of cyclically irreducible words of fixed length in a free group,” in: O. B. Lupanov (ed.), Proc. VIIIth Intern. Seminar “ Discrete Mathematics and Its Applications,” Izd-vo Mekh.-Mat. Fak. MGU, Moscow (2004), pp. 203–204.
L. M. Koganov, “A question of R. I. Grigorchuk and problems connected with it,” in: Proc. VIIth Intern. Seminar “Discrete Mathematics and Its Applications,” Vol. 3, Izd-vo Mekh.-Mat. Fak. MGU, Moscow (2001), pp. 363–364.
I. Rivin, “Growth in free groups (and other stories),” in: arXiv: math. CO/9911076_v 2; (1999), pp. 1–31.
I. Rivin, “Some properties of the conjugacy class growth function,” Contemporary Mathematics, 360, 113–117 (2004).
H. Whitney, “The colorings of graphs,” Ann. Math. (2), 33, 688–718 (1932).
H. Whitney, “A logical expansion in mathematics,” Bull. Amer. Math. Soc., 38, 572–579 (1932).
R. C. Read, “An introduction to chromatic polynomials,” J. Combinat. Theory, 4, No. 1, 52–71 (1968).
M. O. Asanov, V. A. Baranskii, and V. V. Rasin, Discrete Mathematics: Graphs, Matroids, and Algorithms [in Russian], Regular and Chaotic Dynamics (R&C Dynamics), Moscow-Izhevsk (2001).
M. Bocher, Introduction to Higher Algebra [Russian translation], GTTI (1933).
A. D. Mednykh, “Determination of the number of nonequivalent coverings over a compact Riemann surface,” in: Dokl. Akad. Nauk SSSR, 239, No. 2, 269–271 (1978).
A. D. Mednykh, “Branched coverings of Riemann surfaces whose branch orders coincide with the multiplicity,” Comm. in Algebra, 18, No. 5, 1517–1533 (1990).
I. M. Vinogradov, Foundations of Number Theory [in Russian], ONTI, Moscow-Leningrad (1936).
Yu. V. Matiyasevich, “One representation of a chromatic polynomial,” in: Proc. Sobolev Institute of Mathematics SB RAS, Methods of Discrete Analysis in Control Systems Theory, No. 31, 61–70, Novosibirsk (1977).
R. P. Stanley, Enumerative Combinatorics [Russian translation], Vol. 1, Mir, Moscow (1990).
Author information
Authors and Affiliations
Additional information
To the memory of William T. Tutte (05.14.1917–05.02.2002)
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 39–48, July–August 2007.
Rights and permissions
About this article
Cite this article
Koganov, L.M. Number of cyclically irreducible words in the alphabet of a free group of finite rank. Cybern Syst Anal 43, 499–506 (2007). https://doi.org/10.1007/s10559-007-0076-0
Received:
Issue Date:
DOI: https://doi.org/10.1007/s10559-007-0076-0