English

On the pointwise Bishop--Phelps--Bollob\'as property for operators

Functional Analysis 2018-11-20 v2

Abstract

We study approximation of operators between Banach spaces XX and YY that nearly attain their norms in a given point by operators that attain their norms at the same point. When such approximations exist, we say that the pair (X,Y)(X, Y) has the pointwise Bishop-Phelps-Bollob\'as property (pointwise BPB property for short). In this paper we mostly concentrate on those XX, called universal pointwise BPB domain spaces, such that (X,Y)(X, Y) possesses pointwise BPB property for every YY, and on those YY, called universal pointwise BPB range spaces, such that (X,Y)(X, Y) enjoys pointwise BPB property for every uniformly smooth XX. We show that every universal pointwise BPB domain space is uniformly convex and that Lp(μ)L_p(\mu) spaces fail to have this property when p>2p>2. For universal pointwise BPB range space, we show that every simultaneously uniformly convex and uniformly smooth Banach space fails it if its dimension is greater than one. We also discuss a version of the pointwise BPB property for compact operators.

Keywords

Cite

@article{arxiv.1709.00032,
  title  = {On the pointwise Bishop--Phelps--Bollob\'as property for operators},
  author = {Sheldon Dantas and Vladimir Kadets and Sun Kwang Kim and Han Ju Lee and Miguel Martin},
  journal= {arXiv preprint arXiv:1709.00032},
  year   = {2018}
}

Comments

19 pages, to appear in the Canadian J. Math. In this version, section 6 and the appendix of the previous version have been removed