English

A "typical" contraction is unitary

Functional Analysis 2014-12-02 v1 Dynamical Systems

Abstract

We show that (for the weak operator topology) the set of unitary operators on a separable infinite-dimensional Hilbert space is residual in the set of all contractions. The analogous result holds for isometries and the strong operator topology as well. These results are applied to the problem of embedding operators into strongly continuous semigroups.

Keywords

Cite

@article{arxiv.0807.1994,
  title  = {A "typical" contraction is unitary},
  author = {Tanja Eisner},
  journal= {arXiv preprint arXiv:0807.1994},
  year   = {2014}
}

Comments

5 pages

R2 v1 2026-06-21T10:59:55.993Z