Journal of Operator Theory

Volume 50, Issue 2, Fall 2003 pp. 211-220.

Compressions and pinchings

Authors: Jean-Christophe Bourin
Author institution: Les Coteaux, rue Henri Durel 78510 Triel, France

Summary: There exist operators $A$ such that for any sequence of contractions $\{ A_n\}$, there is a total sequence of mutually orthogonal projections $\{ E_n\}$ such that $\sum E_nAE_n=\bigoplus A_n$.

Keywords: compression, dilation, numerical range, pinching

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