English

A Pointwise Lipschitz Selection Theorem

Functional Analysis 2017-08-24 v2

Abstract

We prove that any correspondence (multi-function) mapping a metric space into a Banach space that satisfies a certain pointwise Lipschitz condition, always has a continuous selection that is pointwise Lipschitz on a dense set of its domain. We apply our selection theorem to demonstrate a slight improvement to a well-known version of the classical Bartle-Graves Theorem: Any continuous linear surjection between infinite dimensional Banach spaces has a positively homogeneous continuous right inverse that is pointwise Lipschitz on a dense meager set of its domain. An example devised by Aharoni and Lindenstrauss shows that our pointwise Lipschitz selection theorem is in some sense optimal: It is impossible to improve our pointwise Lipschitz selection theorem to one that yields a selection that is pointwise Lipschitz on the whole of its domain in general.

Keywords

Cite

@article{arxiv.1611.08435,
  title  = {A Pointwise Lipschitz Selection Theorem},
  author = {Miek Messerschmidt},
  journal= {arXiv preprint arXiv:1611.08435},
  year   = {2017}
}