• 대한수학회보
• /
• 제42권3호
• /
• pp.543-554
• /
• 2005

In this paper it is proved that for p-hyponormal or log-hyponormal operator A there exist an associated hyponormal operator T, a quasi-affinity X and an injection operator Y such that TX = XA and AY = YT. The operator A and T have the same spectral picture. We apply these results to give brief proofs of some well known spectral properties of p-hyponormal and log­hyponormal operators, amongst them that the spectrum is a con­tinuous function on these classes of operators.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제12권3호
• /
• pp.161-167
• /
• 2005

In this note we consider the projective property $\sigma(Re(T))\;=\;Re\;(\sigma$(T))$ of p-hyponormal operators and log-hyponormal operators.

• 대한수학회보
• /
• 제42권2호
• /
• pp.269-277
• /
• 2005

The tensor product $A{\bigotimes}B$ of Hilbert space operators A and B will be shown to be log-hyponormal if and only if A and Bare log-hyponormal. Some general comments about generalized hyponormality are also made.

• 대한수학회보
• /
• 제37권1호
• /
• pp.53-62
• /
• 2000

In this paper we explore relations between joint Weyl and Browder spectra. Also, we give a spectral characterization of the Taylor-Browder spectrum for special classes of doubly commuting n-tuples of operators and then give a partial answer to Duggal's question.