English

Self-Induced Compactness in Banach Spaces

Functional Analysis 2016-09-06 v1

Abstract

The question which led to the title of this note is the following: {\it If XX is a Banach space and KK is a compact subset of XX, is it possible to find a compact, or even approximable, operator v:XXv:X\to X such that K\olv(BX)K\subset\ol{v(B_X)}?} This question was first posed by P.G.Dixon [6] in connection with investigating the problem of the existence of approximate identities in certain operator algebras. We shall provide a couple of observations related to the above question and give in particular a negative answer in case of approximable operators. We shall also provide the first examples of Banach spaces having the approximation property but failing the bounded compact approximation property though all of their duals do even have the metric compact approximation property.

Keywords

Cite

@article{arxiv.math/9403210,
  title  = {Self-Induced Compactness in Banach Spaces},
  author = {Peter G. Casazza and Hans Jarchow},
  journal= {arXiv preprint arXiv:math/9403210},
  year   = {2016}
}