×

On log-hyponormal operators. (English) Zbl 0935.47015

The following inequalities are proved: For a log-hyponormal operator \(T\) (i.e., \(T\) is invertible and \(\log T^*T\geq \log TT^*)\) with its polar decomposition \(T= U|T|\), let \(T(s, t)= |T|^sU|T|^t\) with positive numbers \(0< s,t\). Then \[ \{T(s, t)T(s, t)^*\}^{{\min(s,t)\over s+t}}\leq|T|^{2\min(s,t)}\leq \{T(s, t)^* T(s,t)\}^{{\min(s,t)\over s+t}}. \] These inequalities are just same as the case where \(p= 0\) of the results given by the reviewer for a \(p\)-hyponormal operator \(T\) (i.e., \((T^*T)^p\geq (TT^*)^p\) for some \(p>0\)).

MSC:

47A63 Linear operator inequalities
47B20 Subnormal operators, hyponormal operators, etc.
Full Text: DOI

References:

[1] A. Aluthge,On p-hyponormal operators for 0<p<1, Integr. Equat. Oper. Th.,13 (1990), 307-315. · Zbl 0718.47015 · doi:10.1007/BF01199886
[2] A. Aluthge,Some generalized theorems on p-hyponormal operators, Integr. Equat. Oper. Th.,24 (1994). 497-501. · Zbl 0843.47014 · doi:10.1007/BF01191623
[3] A. Aluthge and D. Xia,A trace estimate of (T * T) p -(TT *) p , Integr. Equat. Oper. Th.,12 (1989), 300-303. · Zbl 0682.47008 · doi:10.1007/BF01195118
[4] T. Ando,Operators with a norm condition, Acta Sci. Math.,33, (1972), 169-178. · Zbl 0244.47021
[5] M. Chõ and M. Itoh,Putnam’s inequality for p-hyponormal operators, Proc. Amer. Math. Soc.,123 (1995), 2435-2440. · Zbl 0823.47024
[6] R. E. Curto, P. S. Muhly and D. Xia,A trace estimate for p-hyponormal operators, Integr. Equat. Oper. Th.,6 (1983), 507-514. · Zbl 0519.47011 · doi:10.1007/BF01691913
[7] M. Fujii, J. Jiang, E. Kamei,Characterization of chaotic order and its application to Furuta inequality, Proc. Amer. Math. Soc., (to appear). · Zbl 0889.47014
[8] M. Fujii, J. Jiang, E. Kamei, K. Tanahashi,A characterization of chaotic order and a problem, J. Inequal. Appl.,2, (1988), 149-156. · Zbl 0910.47013 · doi:10.1155/S1025583498000095
[9] M. Fujii and Y. Nakatsu,On subclasses of hyponormal operators, Proc. Japan Acad.,51 (1975), 243-246. · Zbl 0326.47029 · doi:10.3792/pja/1195518627
[10] T. Furuta, A?B?O assures \((B^r A^p B^r )^{\tfrac{1}{q}} \geqslant B^{\tfrac{{p + 2r}}{q}} for{\text{ }}r \geqslant 0, p \geqslant 0,q \geqslant 0{\text{ }}with (1 + 2r)q \geqslant (p + 2r)\) , Proc. Amer. Math. Soc.,101 (1987), 85-88. · Zbl 0721.47023
[11] T. Furuta,Generalized Aluthge transformation on p-hyponormal operators, Proc. Amer. Math. Soc.,124 (1996), 3071-3075. · Zbl 0861.47014 · doi:10.1090/S0002-9939-96-03580-0
[12] T. Furuta and M. Yanagida,Further extension of Aluthge transformation on p-hyponormal operators, Integr. Equat. Oper. Th.,29 (1997), 122-125. · Zbl 0902.47022 · doi:10.1007/BF01191484
[13] T. Furuya,A note on p-hyponormal operators, Proc. Amer. Math. Soc.,125 (1997), 3617-3624. · Zbl 0888.47010 · doi:10.1090/S0002-9939-97-04004-5
[14] E. Heinz,Beiträge zur Störungstheorie der Spektralzerlegung, Math. Ann.123 (1951), 415-438. · Zbl 0043.32603 · doi:10.1007/BF02054965
[15] K. Löwner,Über monotone Matrixfunktionen, Math. Z.,38 (1934), 177-216. · Zbl 0008.11301 · doi:10.1007/BF01170633
[16] S. M. Patel,A note on p-hyponormal operators for 0<p<1 Integr. Equat. Oper. Th.,21 (1995), 498-503. · Zbl 0842.47014 · doi:10.1007/BF01222020
[17] D. Xia,Spectral theory of hyponormal operatots, Birkhauser Verlag, Boston, 1983. · Zbl 0523.47012
[18] T. Yoshino,The p-hyponormality of the Aluthge transform. Interdisciplinary Information Sciences,3 (1997), 91-93. · Zbl 0928.47013 · doi:10.4036/iis.1997.91
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.