Schur products of operators and the essential numerical range
نویسندگان
چکیده
منابع مشابه
On the decomposable numerical range of operators
Let $V$ be an $n$-dimensional complex inner product space. Suppose $H$ is a subgroup of the symmetric group of degree $m$, and $chi :Hrightarrow mathbb{C} $ is an irreducible character (not necessarily linear). Denote by $V_{chi}(H)$ the symmetry class of tensors associated with $H$ and $chi$. Let $K(T)in (V_{chi}(H))$ be the operator induced by $Tin text{End}(V)$. Th...
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15 صفحه اولon the decomposable numerical range of operators
let $v$ be an $n$-dimensional complex inner product space. suppose $h$ is a subgroup of the symmetric group of degree $m$, and $chi :hrightarrow mathbb{c} $ is an irreducible character (not necessarily linear). denote by $v_{chi}(h)$ the symmetry class of tensors associated with $h$ and $chi$. let $k(t)in (v_{chi}(h))$ be the operator induced by $tin text{end}(v)$. the...
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We show that a bounded linear operator A ∈ B(H) is a multiple of a unitary operator if and only if AZ and ZA always have the same numerical radius or the same numerical range for all (rank one) Z ∈ B(H). More generally, for any bounded linear operators A,B ∈ B(H), we show that AZ and ZB always have the same numerical radius (resp., the same numerical range) for all (rank one) Z ∈ B(H) if and on...
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ژورنال
عنوان ژورنال: Transactions of the American Mathematical Society
سال: 1981
ISSN: 0002-9947
DOI: 10.1090/s0002-9947-1981-0597865-2