Davis-wielandt Shells of Operators
نویسنده
چکیده
Basic properties of Davis-Wielandt shells are presented. Conditions on two operators A and B with the same Davis-Wielandt shells are analyzed. Special attention is given to the case when B is a compression of A, and when B = A∗, A, or (A∗)t, where A is the transpose of A with respect to an orthonormal basis. The results are used to study the point spectrum, approximate spectrum, and residual spectrum of the sum of two operators. Relation between the geometrical properties of the Davis-Wielandt shells and algebraic properties of operators are obtained. Complete descriptions of the Davis-Wielandt shells are given for several classes of operators. AMS Subject Classification 47A10, 47A12, 47B15
منابع مشابه
Davis–wielandt Shells of Normal Operators
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تاریخ انتشار 2008