Characterization of the tree cycles with minimum positive entropy for any period

Consider, for any integer n ≥ 3, the set Posn of all n-periodic tree patterns with positive topological entropy and the set Irrn⊂Posn of all n-periodic irreducible tree patterns. The aim of this paper is to determine the elements of minimum entropy in the families Posn, Irrn and Posn∖Irrn. Let λn be...

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Detalles Bibliográficos
Autores: Juher, David|||0000-0001-5440-1705, Mañosas, Francesc|||0000-0003-2535-0501, Rojas, David|||0000-0001-7247-4705
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:326011
Acceso en línea:https://ddd.uab.cat/record/326011
https://dx.doi.org/urn:doi:10.1017/etds.2025.11
Access Level:acceso abierto
Palabra clave:Tree maps
Combinatorial patterns
Periodic orbits
Topological entropy
Descripción
Sumario:Consider, for any integer n ≥ 3, the set Posn of all n-periodic tree patterns with positive topological entropy and the set Irrn⊂Posn of all n-periodic irreducible tree patterns. The aim of this paper is to determine the elements of minimum entropy in the families Posn, Irrn and Posn∖Irrn. Let λn be the unique real root of the polynomial xn-2x-1 in (1,+∞). We explicitly construct an irreducible n-periodic tree pattern Qn whose entropy is log (λn). We prove that this entropy is minimum in Posn. Since the pattern Qn is irreducible, Qn also minimizes the entropy in the family Irrn. We also prove that the minimum positive entropy in the set Posn∖Irrn (which is non-empty only for composite integers n ≥ 6) is log(λn/p)/p, where p is the least prime factor of n.