On transcendence of numbers related to Sturmian and Arnoux-Rauzy words

We consider numbers of the form S_β(u): = ∑_{n=0}^∞ (u_n)/(βⁿ), where u = ⟨u_n⟩_{n=0}^∞ is an infinite word over a finite alphabet and β ∈ ℂ satisfies |β| > 1. Our main contribution is to present a combinatorial criterion on u, called echoing, that implies that S_β(u) is transcendental whenever β...

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Main Authors: Kebis, P, Luca, F, Ouaknine, J, Scoones, A, Worrell, J
Format: Conference item
Language:English
Published: Schloss Dagstuhl – Leibniz-Zentrum für Informatik 2024
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author Kebis, P
Luca, F
Ouaknine, J
Scoones, A
Worrell, J
author_facet Kebis, P
Luca, F
Ouaknine, J
Scoones, A
Worrell, J
author_sort Kebis, P
collection OXFORD
description We consider numbers of the form S_β(u): = ∑_{n=0}^∞ (u_n)/(βⁿ), where u = ⟨u_n⟩_{n=0}^∞ is an infinite word over a finite alphabet and β ∈ ℂ satisfies |β| > 1. Our main contribution is to present a combinatorial criterion on u, called echoing, that implies that S_β(u) is transcendental whenever β is algebraic. We show that every Sturmian word is echoing, as is the Tribonacci word, a leading example of an Arnoux-Rauzy word. We furthermore characterise ̅{ℚ}-linear independence of sets of the form {1, S_β(u₁),…,S_β(u_k)}, where u₁,…,u_k are Sturmian words having the same slope. Finally, we give an application of the above linear independence criterion to the theory of dynamical systems, showing that for a contracted rotation on the unit circle with algebraic slope, its limit set is either finite or consists exclusively of transcendental elements other than its endpoints 0 and 1. This confirms a conjecture of Bugeaud, Kim, Laurent, and Nogueira.
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spelling oxford-uuid:e2fa381d-fc43-420a-885c-3f594e3301ba2024-07-16T10:35:29ZOn transcendence of numbers related to Sturmian and Arnoux-Rauzy wordsConference itemhttp://purl.org/coar/resource_type/c_5794uuid:e2fa381d-fc43-420a-885c-3f594e3301baEnglishSymplectic ElementsSchloss Dagstuhl – Leibniz-Zentrum für Informatik2024Kebis, PLuca, FOuaknine, JScoones, AWorrell, JWe consider numbers of the form S_β(u): = ∑_{n=0}^∞ (u_n)/(βⁿ), where u = ⟨u_n⟩_{n=0}^∞ is an infinite word over a finite alphabet and β ∈ ℂ satisfies |β| > 1. Our main contribution is to present a combinatorial criterion on u, called echoing, that implies that S_β(u) is transcendental whenever β is algebraic. We show that every Sturmian word is echoing, as is the Tribonacci word, a leading example of an Arnoux-Rauzy word. We furthermore characterise ̅{ℚ}-linear independence of sets of the form {1, S_β(u₁),…,S_β(u_k)}, where u₁,…,u_k are Sturmian words having the same slope. Finally, we give an application of the above linear independence criterion to the theory of dynamical systems, showing that for a contracted rotation on the unit circle with algebraic slope, its limit set is either finite or consists exclusively of transcendental elements other than its endpoints 0 and 1. This confirms a conjecture of Bugeaud, Kim, Laurent, and Nogueira.
spellingShingle Kebis, P
Luca, F
Ouaknine, J
Scoones, A
Worrell, J
On transcendence of numbers related to Sturmian and Arnoux-Rauzy words
title On transcendence of numbers related to Sturmian and Arnoux-Rauzy words
title_full On transcendence of numbers related to Sturmian and Arnoux-Rauzy words
title_fullStr On transcendence of numbers related to Sturmian and Arnoux-Rauzy words
title_full_unstemmed On transcendence of numbers related to Sturmian and Arnoux-Rauzy words
title_short On transcendence of numbers related to Sturmian and Arnoux-Rauzy words
title_sort on transcendence of numbers related to sturmian and arnoux rauzy words
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