Patryk Pagacz

activity

20122025

most citedBetween the von Neumann inequality and the Crouzeix conjecture

3 citations · 11 across the 14 of their papers we have counts for

collaborators

Showing math.FAShow all

4 papers · 1 filter

math.FA2019★ 3 cited

Between the von Neumann inequality and the Crouzeix conjecture

Patryk Pagacz, Paweł Pietrzycki, Michał Wojtylak

A new concept of a deformed numerical range $W^{ρ} (T)$ is introduced. Here $T$ is a bounded linear operator or a matrix and $ρ \in [1, + \infty)$ is a parameter. Each $W^{ρ} (T)$ is a clos…

math.FA2017★ 3 cited

Invariant subspaces of $H^{2} (T^{2})$ and $L^{2} (T^{2})$ preserving compatibility

Zbigniew Burdak, Marek Kosiek, Patryk Pagacz +1

Operators of multiplication by independent variables on the space of square summable functions over the torus and its Hardy subspace are considered. Invariant subspaces where the o…

math.FA2014★ 1 cited

The Berberian's transform and an asymmetric Putnam-Fuglede theorem

Ahmed Bachir, Patryk Pagacz

We present how to apply a Berberian's technique to asymmetric Putnam-Fuglede theorems. In particular, we proved that if $A, B \in B (H)$ belong to the union of classes of $*$ -parano…

math.FA2012

On the power-bounded operators of classes $C_{0 \cdot}$ and $C_{1 \cdot}$

Patryk Pagacz

By a bounded backward sequence of the operator $T$ we mean a bounded sequence ${x_{n}}$ satisfying $T x_{n + 1} = x_{n}$ . In \cite{Pa} we have characterized contractions with strongly sta…

Between the von Neumann inequality and the Crouzeix conjecture

Invariant subspaces of H2(T2) and L2(T2) preserving compatibility

The Berberian's transform and an asymmetric Putnam-Fuglede theorem

On the power-bounded operators of classes C0⋅​ and C1⋅​

Invariant subspaces of $H^{2} (T^{2})$ and $L^{2} (T^{2})$ preserving compatibility

On the power-bounded operators of classes $C_{0 \cdot}$ and $C_{1 \cdot}$