摘要
通过数值半径诱导的距离,利用Banach空间上等距理论,给出了一个复数域C上的矩阵空间Mn到自身的单位球面满射Ф保数值域的一个充分条件,即Ф满足Ф(αI+βiI)=αФ(I)+βФ(iI),其中α,β∈R,α^2+β^2=1。
A sufficenent condition of surjective mapping qb preserving numerical range from the unit sphere of matric space Mn over C to itself is given by using the isometric theory and the distance induced by numerical radius. That is Ф satisfies Ф (αI+βiI)=αФ(I)+βФ(iI) for all α,β∈R,α^2+β^2=1.
出处
《军事交通学院学报》
2013年第7期91-93,共3页
Journal of Military Transportation University
关键词
数值域
数值半径
等距
numerical range
numerical radius
isometry