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ENUMERATING NECKLACES WITH TRANSITIONS

Published online by Cambridge University Press:  11 May 2021

FRANCESCO BIANCONI*
Affiliation:
Department of Engineering, Università degli Studi di Perugia, Via Goffredo Duranti 93, 06125 Perugia, Italy
EMANUELE BRUGNOLI
Affiliation:
Communications Regulatory Authority (AGCOM), Centro Direzionale Isola B5, Naples, Italy e-mail: [email protected]

Abstract

Necklaces are the equivalence classes of words under the action of the cyclic group. Let a transition in a word be any change between two adjacent letters modulo the word’s length. We present a closed-form solution for the enumeration of necklaces in n beads, k colours and t transitions. We show that our result provides a more general solution to the problem of counting alternating (proper) colourings of the vertices of a regular n-gon.

Type
Research Article
Copyright
© 2021 Australian Mathematical Publishing Association Inc.

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Footnotes

Partially supported by the Department of Engineering, Università degli Studi di Perugia, Italy, within the project Artificial Intelligence for Earth Observation (Fundamental Research Grant Scheme 2020).

References

Agarwal, A., ‘ $N$ -colour compositions’, Indian J. Pure Appl. Math. 31 (2000), 14211427.Google Scholar
Archer, K. and Lauderdale, L. K., ‘Enumeration of cyclic permutations in vector grid classes’, J. Comb. 11(1) (2020), 203230.Google Scholar
Beeler, R. A., How to Count. An Introduction to Combinatorics and its Applications (Springer, New York, 2015).Google Scholar
Bernstein, D. S. and Kouba, O., ‘Counting colorful necklaces and bracelets in three colors’, Aequationes Math. 93(6) (2019), 11831202.CrossRefGoogle Scholar
Berstel, J. and Perrin, D., ‘The origins of combinatorics on words’, European J. Combin. 28(3) (2007), 9961022.CrossRefGoogle Scholar
Bianconi, F. and Gonzãilez, E., ‘Counting local $n$ -ary patterns’, Pattern Recognit. Lett. 117 (2019), 2429.CrossRefGoogle Scholar
Ferrari, M. M. and Zagaglia Salvi, N., ‘Cyclic compositions and cycles of the hypercube’, Aequationes Math. 92(4) (2018), 671682.CrossRefGoogle Scholar
Heubach, S. and Mansour, T., Combinatorics of Compositions and Words (CRC Press, Boca Raton, FL, 2010).Google Scholar
Kajimoto, H. and Osabe, M., ‘Circular and necklace permutations’, Bull. Fac. Educ. Nagasaki Univ. Nat. Sci. 74 (2006), 114.Google Scholar
Knopfmacher, A. and Robbins, N., ‘Some properties of cyclic compositions’, Fibonacci Quart. 48(3) (2010), 249255.Google Scholar
Ojala, T., Pietikäinen, M. and Mäenpää, T., ‘Multiresolution gray-scale and rotation invariant texture classification with local binary patterns’, IEEE Trans. Pattern Anal. Mach. Intell. 24(7) (2002), 971987.CrossRefGoogle Scholar
Saari, K., ‘Lyndon words and Fibonacci numbers’, J. Combin. Theory Ser. A 121 (2014), 3444.CrossRefGoogle Scholar
Singh, S. and Zelenyuk, Y., ‘Alternating colouring of the vertices of a regular polygon’, Bull. Aust. Math. Soc. 100(2) (2019), 177181.CrossRefGoogle Scholar
Sloane, N. J. A., ‘The On-Line Encyclopedia of Integer Sequences’, https://oeis.org/A000670.Google Scholar