FORWARD TRIPLETS AND TOPOLOGICAL ENTROPY ON TREES

We provide a new and very simple criterion of positive topological entropy for tree maps. We prove that a tree map f has positive entropy if and only if some iterate fk has a periodic orbit with three aligned points consecutive in time, that is, a triplet (a, b, c) such that fk(a) = b, fk(b) = c and...

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Detalles Bibliográficos
Autores: Alsedà, L., Juher, D., Mañosas, F.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2022
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2072/535421
Acceso en línea:http://hdl.handle.net/2072/535421
Access Level:acceso abierto
Palabra clave:Periodic patterns
Topological entropy
Tree maps
Descripción
Sumario:We provide a new and very simple criterion of positive topological entropy for tree maps. We prove that a tree map f has positive entropy if and only if some iterate fk has a periodic orbit with three aligned points consecutive in time, that is, a triplet (a, b, c) such that fk(a) = b, fk(b) = c and b belongs to the interior of the unique interval connecting a and c (a forward triplet of fk). We also prove a new criterion of entropy zero for simplicial n-periodic patterns P based on the non existence of forward triplets of fk for any 1 ≤ k < n inside P. Finally, we study the set Xn of all n-periodic patterns P that have a forward triplet inside P. For any n, we define a pattern that attains the minimum entropy in Xn and prove that this entropy is the unique real root in (1, ∞) of the polynomial xn − 2x − 1. © 2022 American Institute of Mathematical Sciences. All rights reserved.