Similar operator topologies on the space of positive contractions
Abstract
In this article, we study the similarity of the Polish operator topologies , , \texttt{SOT}\mbox{_{*}} and \texttt{SOT}\mbox{^{*}} on the set of the positive contractions on with . Using the notion of norming vector for a positive operator, we prove that these topologies are similar on , that is, they have the same dense sets in . In particular, these topologies will share the same comeager sets in . We then apply these results to the study of typical properties of positive contractions on -spaces in the Baire category sense. In particular, we prove that a typical positive contraction has no eigenvalue. This stands in strong contrast to a result of Eisner and M\'atrai, stating that the point spectrum of a typical contraction contains the whole unit disk. As a consequence of our results, we obtain that a typical positive contraction (resp. T \in (\mathcal{P}_1(\ell_2), \texttt{SOT}\mbox{_{*}})) has no eigenvalue.
Keywords
Cite
@article{arxiv.2412.11587,
title = {Similar operator topologies on the space of positive contractions},
author = {Valentin Gillet},
journal= {arXiv preprint arXiv:2412.11587},
year = {2025}
}
Comments
21 pages