Numerical range for certain classes of operators

Bouldin, Richard

doi:10.1090/S0002-9939-1972-0293424-X

Numerical range for certain classes of operators
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Proc. Amer. Math. Soc. 34 (1972), 203-206 Request permission

Abstract:

We prove a basic result which relates the structure of the spectrum to the interior of the numerical range. Using this result we derive corollaries concerning compact operators, quasinilpotents, and finite dimensional operators. In particular, we characterize finite dimensional convexoid operators.

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