Grzegorz Lewicki

collaborators

3 papers

math.FA2011

Limit Theorems for Numerical Index

Asuman Güven Aksoy, Grzegorz Lewicki

We improve upon on a limit theorem for numerical index for large classes of Banach spaces including vector valued $ℓ_{p}$ -spaces and $ℓ_{p}$ -sums of Banach spaces where $1\leq p…

math.FA2010

Minimal projections with respect to various norms

Asuman Guven Aksoy, Grzegorz Lewicki

We will show that a theorem of Rudin \cite{wr1}, \cite{wr}, permits us to determine minimal projections not only with respect to the operator norm but with respect to quasi-norms i…

math.FA2010

Best Approximation in Numerical Radius

Asuman Guven Aksoy, Grzegorz Lewicki

Let $X$ be a reflexive Banach space. In this paper we give a necessary and sufficient condition for an operator $T \in K (X)$ to have the best approximation in numerical ra…