The paper concerns operators of deformed structure like q-normal and q-hyponormal operators with the deformation parameter q being a positive number different from 1. In particular, an example of a q-hyponormal operator with empty spectrum is given, and q-hyponormality is characterized in terms of some operator inequalities.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm165-3-7,
author = {Sch\^oichi \^Ota and Franciszek Hugon Szafraniec},
title = {Notes on q-deformed operators},
journal = {Studia Mathematica},
volume = {162},
year = {2004},
pages = {295-301},
zbl = {1080.47001},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm165-3-7}
}
Schôichi Ôta; Franciszek Hugon Szafraniec. Notes on q-deformed operators. Studia Mathematica, Tome 162 (2004) pp. 295-301. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm165-3-7/