English

Bollob\'as-type theorems for range strongly exposing operators

Functional Analysis 2025-12-12 v1

Abstract

We study Bollob\'as-type theorems for range strongly exposing operators. When such a theorem holds for operators from a Banach space XX into another Banach space YY, we say that the pair (X,Y)(X,Y) satisfies the Bishop-Phelps-Bollob\'as property for range strongly exposing operators (BPBp-RSE, for short). We provide new characterisations of uniform convexity and complex uniform convexity via the BPBp-RSE, including for pairs involving spaces such as L1(μ),L(μ)L_1(\mu), L_\infty(\mu) and c0c_0. In particular, we show that (L1(μ),Y)(L_1(\mu), Y) satisfies the BPBp-RSE if and only if YY is uniformly convex, and that (L(μ),Y)(L_\infty(\mu), Y) or (c0,Y)(c_0, Y) satisfy the BPBp-RSE if and only if YY is C\mathbb{C}-uniformly convex. We also highlight differences between the real and complex cases, showing that there exist pairs (X,Y)(X, Y) for which the BPBp-RSE holds in the complex setting but fails for their respective underlying real spaces. Additionally, we consider various subspaces of operators, such as compact and finite-rank, and extend several results from the literature to this new setting. The paper concludes with a collection of open problems.

Keywords

Cite

@article{arxiv.2512.10442,
  title  = {Bollob\'as-type theorems for range strongly exposing operators},
  author = {Helena Del Río},
  journal= {arXiv preprint arXiv:2512.10442},
  year   = {2025}
}
R2 v1 2026-07-01T08:20:13.341Z