Positive block matrices and numerical ranges
نویسندگان
چکیده
منابع مشابه
Hermitian octonion matrices and numerical ranges
Notions of numerical ranges and joint numerical ranges of octonion matrices are introduced. Various properties of hermitian octonion matrices related to eigenvalues and convex cones, such as the convex cone of positive semidefinite matrices, are described. As an application, convexity of joint numerical ranges of 2×2 hermitian matrices is characterized. Another application involves existence of...
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Notions of numerical ranges and joint numerical ranges of octonion matrices are introduced. Various properties of hermitian octonion matrices related to eigenvalues and convex cones, such as the convex cone of positive semidefinite matrices, are described. As an application, convexity of joint numerical ranges of 2×2 hermitian matrices is characterized. Another application involves existence of...
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The higher rank numerical range is closely connected to the construction of quantum error correction code for a noisy quantum channel. It is known that if a normal matrix A ∈ Mn has eigenvalues a1, . . . , an, then its higher rank numerical range Λk(A) is the intersection of convex polygons with vertices aj1 , . . . , ajn−k+1 , where 1 ≤ j1 < · · · < jn−k+1 ≤ n. In this paper, it is shown that ...
متن کاملSome results on higher numerical ranges and radii of quaternion matrices
Let $n$ and $k$ be two positive integers, $kleq n$ and $A$ be an $n$-square quaternion matrix. In this paper, some results on the $k-$numerical range of $A$ are investigated. Moreover, the notions of $k$-numerical radius, right $k$-spectral radius and $k$-norm of $A$ are introduced, and some of their algebraic properties are studied.
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ژورنال
عنوان ژورنال: Comptes Rendus Mathematique
سال: 2017
ISSN: 1631-073X
DOI: 10.1016/j.crma.2017.10.006