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On extensions of some Flugede–Putnam type theorems involving ( p, k )‐quasihyponormal, spectral, and dominant operators
Author(s) -
Tanahashi Kotaro,
Patel S. M.,
Uchiyama Atsushi
Publication year - 2009
Publication title -
mathematische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 50
eISSN - 1522-2616
pISSN - 0025-584X
DOI - 10.1002/mana.200610787
Subject(s) - mathematics , hilbert space , integer (computer science) , type (biology) , operator (biology) , discrete mathematics , spectral properties , space (punctuation) , pure mathematics , combinatorics , chemistry , ecology , biochemistry , computational chemistry , repressor , computer science , transcription factor , gene , biology , programming language , linguistics , philosophy
A Hilbert space operator S is called ( p, k )‐quasihyponormal if S * k (( S * S ) p – ( SS *) p ) S k ≥ 0 for an integer k ≥ 1 and 0 < p ≤ 1. In the present note, we consider ( p, k )‐quasihyponormal operator S ∈ B ( H ) such that SX = XT for some X ∈ B ( K,H ) and prove the Fuglede–Putnam type theorems when the adjoint of T ∈ B ( K ) is either ( p, k )‐quasihyponormal or dominant or a spectral operator (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)