| 2. | The subject is related and has applications to many different branches of pure and applied science such as operator theory , functional analysis , c " - algebras , banach algebras , matrix norms , inequalities , numerical analysis , perturbation theory , matrix polynomials , systems theory , quantum physics , etc . in recent years , the quadratic numerical range , one of the most important generalizations of the numerical range , was put forward in the course of people studying the spectral theory of the block operator matrix to the need of the development of some branches mentioned above
对它们的研究涉及到了基础数学及应用数学许多不同的分支，诸如算子理论，泛函分析， c ~ * -代数， banach代数，矩阵范数，不等式，数值分析，扰动性理论，矩阵多项式，系统论，量子物理等等，并且在这些分支上面得到了广泛的应用。近年来，为了上述某些数学分支发展的需要，人们在研究分块算子矩阵谱理论的过程中引入了数值域的一个重要推广：二次数值域。 |
