1. Quasi-projection pairs on Hilbert $C^*$-modules
- Author
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Tian, Xiaoyi, Xu, Qingxiang, and Fu, Chunhong
- Subjects
Mathematics - Operator Algebras ,FOS: Mathematics ,46L08, 47A05 ,Operator Algebras (math.OA) - Abstract
Motivated by a couple of examples, a new term of quasi-projection pair $(P,Q)$ on a Hilbert $C^*$-module $H$ is introduced, in which $P$ is a projection, while $Q$ is an idempotent satisfying certain conditions. Some basic properties of quasi-projection pairs are provided. For every idempotent $Q$ on a Hilbert $C^*$-module $H$, it is shown that there always exist a projection denoted by $m(Q)$, and an invertible operator $W$ on $H$ such that $\big(m(Q),Q\big)$ is a quasi-projection pair satisfying \begin{equation*}Q=W^{-1}PW\quad\mbox{and}\quad \|I-W\
- Published
- 2023
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