@article{oai:niigata-u.repo.nii.ac.jp:00002083,
 author = {Cho, Muneo and Huruya, Tadashi},
 issue = {2},
 journal = {Journal of the Mathematical Society of Japan},
 month = {},
 note = {Let T = U|T| be a bounded linear operator with the associated polar decomposition on a separable infinite dimensional Hilbert space. For 0 < t < 1, let Tt = |T|tU|T|1-t and gT and gTt be the principal functions of T and Tt, respectively. We show that, if T is an invertible semi-hyponormal operator with trace class commutator [|T|,U], then gT = gTt almost everywhere on C. As a biproduct we reprove Berger's theorem and index properties of invertible p-hyponormal operators},
 pages = {605--618},
 title = {Relations between principal functions of p-hyponormal operators : Dedicated to Professor Sin-Ei Takahasi on his sixtieth birthday},
 volume = {57},
 year = {2005}
}