Extreme contractions on finite-dimensional Banach spaces

Autorzy

Dane publikacji

  • DOI: 10.4064/cm8803-7-2022

  • Tom 172

  • Zeszyt 1

  • Czasopismo: Colloquium Mathematicum

  • Strony: 65-83

  • Data publikacji online: 23.10.2022

Liczba wyświetleń: 0

Liczba pobrań: 0

Abstrakt

We study extreme contractions in the setting of finite-dimensional polyhedral Banach spaces. Motivated by the famous Krein–Milman Theorem, we prove that a rank $1$ linear operator of unit norm between such spaces can be expressed as a convex combination of rank $1$ extreme contractions whenever the domain is two-dimensional. We establish that the same result holds true in the space of all linear operators from $\ell _{\infty }^n(\mathbb C) $ to $ \ell _1^n (\mathbb C). $ Furthermore, we present a geometric characterization of extreme contractions between finite-dimensional polyhedral Banach spaces.