一类无界算子的二次数值域和谱

邱汶汶,齐雅茹

The Quadratic Numerical Range and the Spectrum of Some Unbounded Block Operator Matrices

Wenwen Qiu,Yaru Qi

图 4 定理3.3 $ k = \frac{1}{2}, \delta = 1.05, \xi = 4 $