Browsing by Author "Hadjiloucas, Demetris"
Now showing items 112 of 12

Dynamics of tuples of matrices
Costakis, George; Hadjiloucas, Demetris; Manoussos, Antonios (20090301)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 ntuples (A1,A2,...,An) of ... 
Extended abstract theory of universal series and applications
Hadjiloucas, Demetris (20090901)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 superstrong wilf equivalence classes of permutations
Hadjiloucas, Demetris; Michos, Ioannis C.; Savvidou, Christina (20180622)Superstrong 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, nonhypercyclic tuple
Costakis, George; Hadjiloucas, Demetris; Manoussos, Antonios (20100501)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 skewproduct systems
Broomhead, David S.; Hadjiloucas, Demetris; Nicol, Matthew J. (19990101)This paper is concerned with the stability properties of skewproducts 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 skewproduct systems
Broomhead, David S.; Hadjiloucas, Demetris; Nicol, Matthew J. (19991201)This paper is concerned with the stability properties of skewproducts 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. (20020826)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 (20061201)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 matrixvalued cocycles and nonhomogeneous markov chains
Hadjiloucas, Demetris (20070101)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 (20090901)Let T be a linear continuous operator acting on a Banach space X and {λn} a sequence of nonzero complex numbers satisfying λn+ 1/λn → 1. In this article we look at sequences of operators of the form {λnTn}. In earlier ... 
Topologically transitive skewproducts of backward shift operators and hypercyclicity
Costakis, George; Hadjiloucas, Demetris (20080301)In this article we look at skewproducts of multiples of the backward shift and examine conditions under which the skewproduct is topologically transitive or hypercyclic in the second coordinate. We also give an application ... 
Topologically transitive skewproducts of operators
Bayart, Frédéric; Costakis, George; Hadjiloucas, Demetris (20100201)The purpose of the present paper is to provide a link between skewproduct systems and linear dynamics. In particular, we give a criterion for skewproducts of linear operators to be topologically transitive. This is then ...