English

Jointly hyponormal pairs of commuting subnormal operators need not be jointly subnormal

Functional Analysis 2007-05-23 v1

Abstract

We construct three different families of commuting pairs of subnormal operators, jointly hyponormal but not admitting commuting normal extensions. Each such family can be used to answer in the negative a 1988 conjecture of R. Curto, P. Muhly and J. Xia. We also obtain a sufficient condition under which joint hyponormality does imply joint subnormality.

Cite

@article{arxiv.math/0405587,
  title  = {Jointly hyponormal pairs of commuting subnormal operators need not be jointly subnormal},
  author = {Raul Curto and Jasang Yoon},
  journal= {arXiv preprint arXiv:math/0405587},
  year   = {2007}
}

Comments

20 pages, 7 figures

R2 v1 2026-07-22T17:06:05.597Z