Generalized Fuglede-Putnam Theorem and $m$-quasi-class $A(k)$ operators
Keyword(s):
Class A
◽
For a bounded linear operator $T$ acting on acomplex infinite dimensional Hilbert space $\h,$ we say that $T$is $m$-quasi-class $A(k)$ operator for $k>0$ and $m$ is apositive integer (abbreviation $T\in\QAkm$) if$T^{*m}\left((T^*|T|^{2k}T)^{\frac{1}{k+1}}-|T|^2\right)T^m\geq0.$ The famous {\it Fuglede-Putnam theorem} asserts that: the operator equation$AX=XB$ implies $A^*X=XB^*$ when $A$ and $B$ are normal operators.In this paper, we prove that if $T\in \QAkm$ and $S^*$ isan operator of class $A(k)$ for $k>0$. Then $TX=XS$, where $X\in\bh$ is an injective with dense range implies $XT^*=S^*X$.
1989 ◽
Vol 32
(3)
◽
pp. 320-326
◽
1969 ◽
Vol 21
◽
pp. 1421-1426
◽
1986 ◽
Vol 41
(1)
◽
pp. 47-50
◽
1969 ◽
Vol 12
(5)
◽
pp. 639-643
◽
2001 ◽
Vol 44
(4)
◽
pp. 469-481
◽
2010 ◽
Vol 10
(2)
◽
pp. 325-348
◽
2006 ◽
Vol 136
(5)
◽
pp. 935-944
◽