English

Diameter two properties in some vector-valued function spaces

Functional Analysis 2021-03-17 v2

Abstract

We introduce a vector-valued version of a uniform algebra, called the vector-valued function space over a uniform algebra. The diameter two properties of the vector-valued function space over a uniform algebra on an infinite compact Hausdorff space are investigated. Every nonempty relatively weakly open subset of the unit ball of a vector-valued function space A(K,(X,τ))A(K, (X, \tau)) over an infinite dimensional uniform algebra has the diameter two, where τ\tau is a locally convex Hausdorff topology on a Banach space XX compatible to a dual pair. Under the assumption on XX being uniformly convex with norm topology τ\tau and the additional condition that AXA(K,X)A\otimes X\subset A(K, X), it is shown that Daugavet points and Δ\Delta-points on A(K,X)A(K, X) over a uniform algebra AA are the same, and they are characterized by the norm-attainment at a limit point of the Shilov boundary of AA. In addition, a sufficient condition for the convex diametral local diameter two property of A(K,X)A(K,X) is also provided. As a result, the similar results also hold for an infinite dimensional uniform algebra.

Keywords

Cite

@article{arxiv.2103.04012,
  title  = {Diameter two properties in some vector-valued function spaces},
  author = {Han Ju Lee and Hyung-Joon Tag},
  journal= {arXiv preprint arXiv:2103.04012},
  year   = {2021}
}
R2 v1 2026-06-23T23:49:39.429Z