scholarly journals $q$-Frequently hypercyclic operators

2015 ◽  
Vol 9 (2) ◽  
pp. 114-126 ◽  
Author(s):  
Manjul Gupta ◽  
Aneesh Mundayadan
2006 ◽  
Vol 358 (11) ◽  
pp. 5083-5117 ◽  
Author(s):  
Frédéric Bayart ◽  
Sophie Grivaux

2013 ◽  
Vol 35 (3) ◽  
pp. 691-709 ◽  
Author(s):  
FRÉDÉRIC BAYART ◽  
IMRE Z. RUZSA

AbstractWe solve several problems on frequently hypercyclic operators. Firstly, we characterize frequently hypercyclic weighted shifts on${\ell }^{p} ( \mathbb{Z} )$,$p\geq 1$. Our method uses properties of the difference set of a set with positive upper density. Secondly, we show that there exists an operator which is$ \mathcal{U} $-frequently hypercyclic but not frequently hypercyclic, and that there exists an operator which is frequently hypercyclic but not distributionally chaotic. These (surprising) counterexamples are given by weighted shifts on${c}_{0} $. The construction of these shifts lies on the construction of sets of positive integers whose difference sets have very specific properties.


Author(s):  
Quentin Menet

Abstract We show that there exists an invertible frequently hypercyclic operator on $\ell ^1(\mathbb {N})$ whose inverse is not frequently hypercyclic.


2020 ◽  
pp. 1-37
Author(s):  
STÉPHANE CHARPENTIER ◽  
KARL GROSSE-ERDMANN ◽  
QUENTIN MENET

Abstract Bayart and Ruzsa [Difference sets and frequently hypercyclic weighted shifts. Ergod. Th. & Dynam. Sys.35 (2015), 691–709] have recently shown that every frequently hypercyclic weighted shift on $\ell ^p$ is chaotic. This contrasts with an earlier result of Bayart and Grivaux [Frequently hypercyclic operators. Trans. Amer. Math. Soc.358 (2006), 5083–5117], who constructed a non-chaotic frequently hypercyclic weighted shift on $c_0$ . We first generalize the Bayart–Ruzsa theorem to all Banach sequence spaces in which the unit sequences form a boundedly complete unconditional basis. We then study the relationship between frequent hypercyclicity and chaos for weighted shifts on Fréchet sequence spaces, in particular, on Köthe sequence spaces, and then on the special class of power series spaces. We obtain, rather curiously, that every frequently hypercyclic weighted shift on $H(\mathbb {D})$ is chaotic, while $H(\mathbb {C})$ admits a non-chaotic frequently hypercyclic weighted shift.


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