一个数值半径不等式

A Numerical Radius Ineqalutids

对于Hilbert空间上的有界算子A,有不等式,1/4‖A*A+AA*‖≤(w(A))2≤1/2‖A*A+AA*‖,其中,w(.)和‖.‖是数值半径和常用算子范数.用它证明一个非常重要的不等式.1/2‖A‖≤w(A)≤‖A‖.

It is show that if A is abounded linear operaator on a complex space, then, and these inequaluties can prove the well know inequalities