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Main Authors: Berthé, Valérie, Puzynina, Svetlana
Format: Preprint
Published: 2022
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Online Access:https://arxiv.org/abs/2205.07707
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author Berthé, Valérie
Puzynina, Svetlana
author_facet Berthé, Valérie
Puzynina, Svetlana
contents An infinite word generated by a substitution is rigid if all the substitutions which fix this word are powers of a same substitution. Sturmian words as well as characteristic Arnoux-Rauzy words are known to be rigid. In the present paper, we prove that all Arnoux-Rauzy words are rigid. The proof relies on two main ingredients: firstly, the fact that the primitive substitutions that fix an Arnoux-Rauzy word share a common power, and secondly, the notion of normal form of an episturmian substitution (i.e., a substitution that fixes an Arnoux-Rauzy word). The main difficulty is then of a combinatorial nature and relies on the normalization process when taking powers of episturmian substitutions: the normal form of a square is not necessarily equal to the square of the normal forms.
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publishDate 2022
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spellingShingle On the rigidity of Arnoux-Rauzy words
Berthé, Valérie
Puzynina, Svetlana
Discrete Mathematics
An infinite word generated by a substitution is rigid if all the substitutions which fix this word are powers of a same substitution. Sturmian words as well as characteristic Arnoux-Rauzy words are known to be rigid. In the present paper, we prove that all Arnoux-Rauzy words are rigid. The proof relies on two main ingredients: firstly, the fact that the primitive substitutions that fix an Arnoux-Rauzy word share a common power, and secondly, the notion of normal form of an episturmian substitution (i.e., a substitution that fixes an Arnoux-Rauzy word). The main difficulty is then of a combinatorial nature and relies on the normalization process when taking powers of episturmian substitutions: the normal form of a square is not necessarily equal to the square of the normal forms.
title On the rigidity of Arnoux-Rauzy words
topic Discrete Mathematics
url https://arxiv.org/abs/2205.07707