This thesis is divided into four chapters. In the first one, we give some preliminaries by mentioning some definitions and known results that will be of great help later.In chapter 2, we introduce a refinement of the notion of hypercyclicity, relative to the set N (U, V ) = {n ∈ N : T −n U ∩ V = ∅} when belonging to a certain collection F of subsets of N, namely a bounded and linear operator T is called F -operator if N (U, V ) ∈ F , for any pair of non-empty open sets U, V in X. First, we do an analysis of the hierarchy established between F -operators, whenever F covers those families mostly studied in Ramsey theory. Second, we investigate which kind of properties of density can the sets N (x, U ) = {n ∈ N : T n x ∈ U } and N (U, V ) have for a given hypercyclic operator, and classify the hypercyclic operators accordingly to these properties.In chapter three, we introduce the following notion: an operator T on X satisfies property P F if for any U non-empty open set in X, there exists x ∈ X such that N (x, U ) ∈ F . Let BD the collection of sets in N with positive upper Banach density. We generalize the main result of (19) using a strong result of Bergelson and Mccutcheon (10) in the vein of Szemerédi's theorem, leading us to a characterization of those operators satisfying property P BD . It turns out that operators having property P BD satisfy a kind of recurrence described in terms of essential idempotents of βN (the Stone-Čech compactification of N). We will discuss the case of weighted backward shifts satisfying property P BD . On the other hand, as a consequence we obtain a characterization of reiteratively hypercyclic operators, i.e. operators for which there exists x ∈ X such that for any U non-empty open set in X, the set N (x, U ) ∈ BD. We also, investigate the relationship between reiteratively hypercyclic operators and d-F tuples, for filters F contained in the family of syndetic sets. Finally, we examine conditions to impose in order to get reiterative hypercyclicity from syndeticity in the weighted shift frame.
ResumenUn operador lineal y acotado se dice hipercíclico si existe un vector cuya órbita es densa. El primer ejemplo de operador hipercíclico sobre un espacio de Banach fue dado por Rolewicz en 1969, quien prueba que B es hipercíclico si y sólo si |λ| > 1, para B operador desplazamiento unilateral en l 2 . Entre los primeros resultados vinculados a la hiperciclicidad podríamos mencionar el hecho que ningún espacio finito dimensional puede soportar un operador hipercíclico y que en el contexto de los espacios de Hilbert, todo operador hipercíclico tiene un conjunto G δ -denso de vectores hipercíclicos.La tesis está dividida en cuatro capítulos. En el primero, se dan algunos preliminares, repasando aquellas definiciones y resultados ya existentes en la literatura que nos serán necesarios más adelante.En el capítulo dos, introducimos un refinamiento del conceptoT −n U ∩ V = ∅}, cuando éste pertenece a una cierta colección de subconjuntos de N. En otras palabras, un operador lineal y continuo ...