numerical range短语¹¹⁴⁴⁶⁷⁺⁴ 基本例句 数值范围 Lastly, we show some inequalities about invariant norms of matrix. In chapter 4, firstly, we investigate the properties of contraction by using spectrum norm, numerical range. 最后证明了一些酉不变范数不等式。第四章，首先以谱范数，数值域为工具，刻画了压缩矩阵的性质； fabiao