10 citations · 18 across the 10 of their papers we have counts for
11 papers
Simultaneous approximation of translation operators
Nikos Tsirivas
We prove the existence of entire functions that achieve universal approximations on certain countable sequences of translation operators .
A solution of polynomial equations
Nikos Tsirivas
We present a method for the solution of polynomial equations. We do not intend to present one more method among several others, because today there are many excellent methods. Our…
Common hypercyclic vectors and universal functions
George Costakis, Nikos Tsirivas
Let X,Y be two separable Banach or Frechet spaces , and (Tn) , n=1,2,... be a sequence from linear and continuous operators from X to Y . We say that the sequence (Tn) , n=1,2,...…
Common hypercyclic vectors for certain families of differential operators
Nikos Tsirivas
Let (k(n)) n=1,2,... be a strictly increasing sequence of positive integers . We consider a specific sequence of differential operators Tk(n),λ , n=1,2,... on the space of entire f…
Common hypercyclic vectors for families of backward shift operators
Nikos Tsirivas
We provide necessary and sufficient conditions on the existence of common hypercyclic vectors for multiples of the backward shift operator along sparse powers. Our main result stro…
Universal Taylor series on specific compact sets
Nikos Tsirivas
Let be the open unit disc in the complex plane. We denote by the set of complex numbers and consider any compact set which is disjoint from and which also…
A general lower bound for the asymptotic convergence factor
Nikos Tsirivas
We provide a rather general and very simple to compute lower bound for the asymptotic convergence factor of compact subsets of the set of complex numbers with connected complement…
Common hypercyclic functions for translation operators with large gaps II
Nikos Tsirivas
We prove the existence of common hypercyclic entire functions for uncountable families of translation type operators. Contrary to our previous work [34], here the parameter which r…
Non-existence of common hypercyclic entire functions for certain families of translation operators
George Costakis, Nikos Tsirivas, Vagia Vlachou
We show that families of translation operators, where the translates grow exponentially fast, do not admit common hypercyclic functions. The result is close to be optimal.
Common hypercyclic functions for translation operators with large gaps
Nikos Tsirivas
We prove the existence of common hypercyclic, entire functions for certain uncountable families of traslation type operators with relative large gaps.
Existence of common hypercyclic vectors for translation operators
Nikos Tsirivas
We prove the existence of common hypercyclic, entire functions for certain families of translation operators.