Invariance of numerical range under isometric transformation

African Journal of Mathematics and Computer Science Research

A. W. Wafula¹ 

关键词: Numerical range and unitary operator.;   

DOI  :  

学科分类：计算机科学（综合）

来源: Academic Journals

【 摘 要 】

In this paper, we look at some properties of isometries and conditions for a quasi-affinity to beunitary. Among other results it is proved thatif A is a partial isometry such that either 0єW(A) or 0єW(An)for some positive integer n then A is unitary.

【 授权许可】

CC BY