English

Domination of operators in the non-commutative setting

Operator Algebras 2013-10-18 v2 Functional Analysis

Abstract

We consider majorization problems in the non-commutative setting. More specifically, suppose EE and FF are ordered normed spaces (not necessarily lattices), and 0TS:EF0 \leq T \leq S :E \to F. If SS belongs to a certain ideal (for instance, the ideal of compact or Dunford-Pettis operators), does it follow that TT belongs to that ideal as well? We concentrate on the case when EE and FF are CC^*-algebras, preduals of von Neumann algebras, or non-commutative function spaces. In particular, we show that, for CC^*-algebras \A\A and B{\mathcal{B}}, the following are equivalent: (1) at least one of the two conditions holds: (i) \A\A is scattered, (ii) B{\mathcal{B}} is compact; (2) if 0TS:\AB0 \leq T \leq S : \A \to {\mathcal{B}}, and SS is compact, then TT is compact.

Keywords

Cite

@article{arxiv.1209.0699,
  title  = {Domination of operators in the non-commutative setting},
  author = {Timur Oikhberg and Eugeniu Spinu},
  journal= {arXiv preprint arXiv:1209.0699},
  year   = {2013}
}
R2 v1 2026-06-21T21:59:38.975Z