Cone-fields without constant orbit core dimension
Author(s) -
Tomasz Kułaga,
Jacek Tabor,
Łukasz Struski
Publication year - 2012
Publication title -
discrete and continuous dynamical systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 70
eISSN - 1553-5231
pISSN - 1078-0947
DOI - 10.3934/dcds.2012.32.3651
Subject(s) - expansive , cone (formal languages) , dimension (graph theory) , physics , orbit (dynamics) , lambda , constant (computer programming) , metric space , field (mathematics) , combinatorics , space (punctuation) , mathematical physics , mathematical analysis , mathematics , pure mathematics , quantum mechanics , linguistics , philosophy , compressive strength , algorithm , computer science , engineering , thermodynamics , programming language , aerospace engineering
As is well-known, the existence of a cone-field with constant orbit core dimension is, roughly speaking, equivalent to hyperbolicity, and consequently guarantees expansivity and shadowing. In this paper we study the case when the given cone-field does not have the constant orbit core dimension. It occurs that we still obtain expansivity even in general metric spaces. Main Result. Let $X$ be a metric space and let $f:X \rightharpoonup X$ be a given partial map. If there exists a uniform cone-field on $X$ such that $f$ is cone-hyperbolic, then $f$ is uniformly expansive, i.e. there exists $N \in \mathbb{N}$, $\lambda \in [0,1)$ and $\epsilon > 0$ such that for all orbits $\mathrm{x},\mathrm{v}:{-N,\ldots,N} \to X$ \[ d_{\sup}(\mathrm{x},\mathrm{v}) \leq \epsilon \Longrightarrow d(\mathrm{x}_0,\mathrm{v}_0) \leq \lambda d_{\sup}(\mathrm{x},\mathrm{v}). \] } We also show a simple example of a cone hyperbolic orbit in $\mathbb{R}^3$ which does not have the shadowing property.
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