中文

Operators preserving orthogonality are isometries

泛函分析 2008-02-03 v1

摘要

Let EE be a real Banach space. For x,yE,x,y \in E, we follow R.James in saying that xx is orthogonal to yy if x+αyx\|x+\alpha y\|\geq \|x\| for every αR\alpha \in R. We prove that every operator from EE into itself preserving orthogonality is an isometry multiplied by a constant.

关键词

引用

@article{arxiv.math/9212203,
  title  = {Operators preserving orthogonality are isometries},
  author = {Alexander Koldobsky},
  journal= {arXiv preprint arXiv:math/9212203},
  year   = {2008}
}