Abstract
We show that, up to renaming of the letters, the only infinite ternary words avoiding the formula ABCAB.ABCBA.ACB.BAC (resp. ABCA.BCAB.BCB.CBA) have the same set of recurrent factors as the fixed point of \(\texttt {0}\mapsto \texttt {012}\), \(\texttt {1}\mapsto \texttt {02}\), \(\texttt {2}\mapsto \texttt {1}\).
Also, we show that the formula ABAC.BACA.ABCA is 2-avoidable. Finally, we show that the pattern ABACADABCA is unavoidable for the class of \(C_4\)-minor-free graphs with maximum degree 3. This disproves a conjecture of Grytczuk.
This work was partially supported by the ANR project CoCoGro (ANR-16-CE40-0005).
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Berstel, J.: Axel Thue’s papers on repetitions in words: a translation, vol. 20. Publications du LACIM. Université du Québec à Montréal (1994)
Cassaigne, J.: Motifs évitables et régularité dans les mots. Ph.D. thesis, Université Paris VI (1994)
Grytczuk, J.: Pattern avoidance on graphs. Discrete Math. 307(11–12), 1341–1346 (2007)
Thue, A.: Über unendliche Zeichenreihen. Norske Vid. Selsk. Skr. I. Mat. Nat. Kl. Christiania 7, 1–22 (1906)
Thue, A.: Über die gegenseitige Lage gleicher Teile gewisser Zeichenreihen. Norske Vid. Selsk. Skr. I. Mat. Nat. Kl. Christiania 10, 1–67 (1912)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2017 Springer International Publishing AG
About this paper
Cite this paper
Ochem, P., Rosenfeld, M. (2017). On Some Interesting Ternary Formulas. In: Brlek, S., Dolce, F., Reutenauer, C., Vandomme, É. (eds) Combinatorics on Words. WORDS 2017. Lecture Notes in Computer Science(), vol 10432. Springer, Cham. https://doi.org/10.1007/978-3-319-66396-8_4
Download citation
DOI: https://doi.org/10.1007/978-3-319-66396-8_4
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-66395-1
Online ISBN: 978-3-319-66396-8
eBook Packages: Computer ScienceComputer Science (R0)