摘要
1.设A是可析Hilbert空间H中的线性有界算子。记■作A的如下的极分解■其中U是以■为定义域,■为值域的等距算子。此后我们总是把U任意地延拓为H上的部分等距算子。
Let A be a bounded linear operator and Q=(A^(*)A)-(AA^(*))^(1/2)≥0.If A=U|A|is the polar decomposition of A,then there exist the polar symbols A_(+)=■U^(*n)AU^(n),A^(-)=■U^(n)AU^(*n).The relationship between the spectra of the operators A,U,|A|and Aare considered,the singular integral model of A is established,and the inequality||Q||≤1/2πμ_(ψ)(σ(A))is proved for a certain class of such operators A.
出处
《科学通报》
1979年第17期773-777,共5页
Chinese Science Bulletin
