Grzegorz Lewicki

collaborators

3 papers

math.FA2026

Finite-codimensional subspaces of Daugavet spaces: projection constants and minimal projections

Tomasz Kania, Grzegorz Lewicki

Over the real or complex field, we establish a duality formula for projection constants of finite-codimensional subspaces of Banach spaces with the Daugavet property. If \[ Y=\bigc…

math.FA2026

$(I^»^{+})$ -injective Banach spaces

Tomasz Kania, Grzegorz Lewicki

In a companion paper (Studia Math., 2023), we proved for every $I^» \in (1, 2]$ the existence of a $(I^»^{+})$ -injective renorming of $ℓ_{\infty}$ that is not $I^»$ -injective, thereby est…

math.FA2025

$2$ -strong uniqueness of a best approximation and of minimal projections in complex polytope norms and their duals

Tomasz Kobos, Grzegorz Lewicki

We study a property of $2$ -strong uniqueness of a best approximation in a class of finite-dimensional complex normed spaces, for which the unit ball is an absolutely convex hull of…

Finite-codimensional subspaces of Daugavet spaces: projection constants and minimal projections

(I^»+)-injective Banach spaces

2-strong uniqueness of a best approximation and of minimal projections in complex polytope norms and their duals

$(I^»^{+})$ -injective Banach spaces

$2$ -strong uniqueness of a best approximation and of minimal projections in complex polytope norms and their duals