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Discrete and Continuous Dynamical Systems - Series A (DCDS-A)
 

Random graph directed Markov systems

Pages: 261 - 298, Volume 30, Issue 1, May 2011

doi:10.3934/dcds.2011.30.261       Abstract        References        Full Text (537.8K)       Related Articles

Mario Roy - Glendon College, York University, 2275 Bayview Avenue, Toronto, Canada (email)
Mariusz UrbaƄski - Department of Mathematics, University of North Texas, P.O. Box 311430, Denton, TX 76203-1430, United States (email)

Abstract: We introduce and explore random conformal graph directed Mar-kov systems governed by measure-preserving ergodic dynamical systems. We first develop the symbolic thermodynamic formalism for random finitely primitive subshifts of finite type with a countable alphabet (by establishing tightness in a narrow topology). We then construct fibrewise conformal and invariant measures along with fibrewise topological pressure. This enables us to define the expected topological pressure $\mathcal EP(t)$ and to prove a variant of Bowen's formula which identifies the Hausdorff dimension of almost every limit set fiber with $\inf\{t:\mathcal EP(t)\leq0\}$, and is the unique zero of the expected pressure if the alphabet is finite or the system is regular. We introduce the class of essentially random systems and we show that in the realm of systems with finite alphabet their limit set fibers are never homeomorphic in a bi-Lipschitz fashion to the limit sets of deterministic systems; they thus make up a drastically new world. We also provide a large variety of examples, with exact computations of Hausdorff dimensions, and we study in detail the small random perturbations of an arbitrary elliptic function.

Keywords:  Iterated function systems, random dynamical systems, limit set, Hausdorff dimension, thermodynamic formalism, countable shifts, elliptic functions.
Mathematics Subject Classification:  Primary: 37H99, 37D35, 37F35; Secondary: 37F10.

Received: January 2010;      Revised: October 2010;      Published: February 2011.

 References