Now showing items 1-12 of 12

    • Dynamics of tuples of matrices 

      Costakis, George; Hadjiloucas, Demetris; Manoussos, Antonios (2009-03-01)
      In this article we answer a question raised by N. Feldman in 2008 concerning the dynamics of tuples of operators on ℝn. In particular, we prove that for every positive integer n ≥ 2 there exist n-tuples (A1,A2,...,An) of ...
    • Extended abstract theory of universal series and applications 

      Hadjiloucas, Demetris (2009-09-01)
      In this article, we extend the recently developed abstract theory of universal series to include averaged sums of the form 1/Φ(n) ∑n j=0ajxj for a given fixed sequence of vectors (xj) in a topological vector space X over ...
    • On super-strong wilf equivalence classes of permutations 

      Hadjiloucas, Demetris; Michos, Ioannis C.; Savvidou, Christina (2018-06-22)
      Super-strong Wilf equivalence is a type of Wilf equivalence on words that was originally introduced as strong Wilf equivalence by Kitaev et al. [Electron. J. Combin. 16(2)] in 2009. We provide a necessary and sufficient ...
    • On the minimal number of matrices which form a locally hypercyclic, non-hypercyclic tuple 

      Costakis, George; Hadjiloucas, Demetris; Manoussos, Antonios (2010-05-01)
      In this paper we extend the notion of a locally hypercyclic operator to that of a locally hypercyclic tuple of operators. We then show that the class of hypercyclic tuples of operators forms a proper subclass to that of ...
    • Random and deterministic perturbation of a class of skew-product systems 

      Broomhead, David S.; Hadjiloucas, Demetris; Nicol, Matthew J. (1999-01-01)
      This paper is concerned with the stability properties of skew-products T (x, y) = (f(x), g(x, y)) in which (f, X, μ) is an ergodic map of a compact metric space X and g: X x ℝn → ℝn is continuous. We assume that the ...
    • Random and deterministic perturbation of a class of skew-product systems 

      Broomhead, David S.; Hadjiloucas, Demetris; Nicol, Matthew J. (1999-12-01)
      This paper is concerned with the stability properties of skew-products T (x, y) = (f(x), g(x, y)) in which (f, X, μ) is an ergodic map of a compact metric space X and g: X x ℝn → ℝn is continuous. We assume that the ...
    • Regularity of invariant graphs over hyperbolic systems 

      Hadjiloucas, Demetris; Nicol, Matthew J.; Walkden, Charles P. (2002-08-26)
      We consider cocycles with negative Lyapunov exponents defined over a hyperbolic dynamical system. It is well known that such systems possess invariant graphs and that under spectral assumptions these graphs have some degree ...
    • Somewhere dense Cesàro orbits and rotations of Cesàro hypercyclic operators 

      Costakis, George; Hadjiloucas, Demetris (2006-12-01)
      Let T be a continuous linear operator acting on a Banach space X. We examine whether- certain fundamental results for hypercyclic operators are still valid in the Cesàro hypercyclicity setting. In particular, in connection ...
    • Stochastic matrix-valued cocycles and non-homogeneous markov chains 

      Hadjiloucas, Demetris (2007-01-01)
      We prove weak ergodicity theorems for non - homogeneous Markov chains {XV}V≥0 taking values in a finite state space S = {1, ⋯, n} for which the family of transition matrices {g(x)} xεX is generated from some underlying ...
    • The hypercyclicity criterion and hypercyclic sequences of multiples of operators 

      Costakis, George; Hadjiloucas, Demetris (2009-09-01)
      Let T be a linear continuous operator acting on a Banach space X and {λn} a sequence of non-zero complex numbers satisfying λn+ 1/λn → 1. In this article we look at sequences of operators of the form {λnTn}. In earlier ...
    • Topologically transitive skew-products of backward shift operators and hypercyclicity 

      Costakis, George; Hadjiloucas, Demetris (2008-03-01)
      In this article we look at skew-products of multiples of the backward shift and examine conditions under which the skew-product is topologically transitive or hypercyclic in the second coordinate. We also give an application ...
    • Topologically transitive skew-products of operators 

      Bayart, Frédéric; Costakis, George; Hadjiloucas, Demetris (2010-02-01)
      The purpose of the present paper is to provide a link between skew-product systems and linear dynamics. In particular, we give a criterion for skew-products of linear operators to be topologically transitive. This is then ...