Georgios Tsikalas

collaborators

3 papers

math.FA2022

Interpolating sequences for pairs of spaces

Georgios Tsikalas

We characterize interpolating sequences for pairs of reproducing kernels $(s, ℓ)$ , where $s$ is a complete Pick factor of $ℓ .$ This answers a question of Aleman, Hartz, McCar…

math.FA2021

A von Neumann type inequality for an annulus

Georgios Tsikalas

Let $A_{r} = {r < ∣ z ∣ < 1}$ be an annulus. We consider the class of operators $F_{r} := {T \in B (H) : r^{2} T^{- 1} (T^{- 1})^{*} + T T^{*} \leq r^{2} + 1, σ (T) \subset A_{r}}$ a…

math.FA2021

A note on a spectral constant associated with an annulus

Georgios Tsikalas

Fix $R > 1$ and let $A_{R} = {1/ R \leq ∣ z ∣ \leq R}$ be an annulus. Also, let $K (R)$ denote the smallest constant such that $A_{R}$ is a $K (R)$ -spectral set for the bounded linear operator $…