On higher rank numerical hulls of normal matrices
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Abstract:
In this paper, some algebraic and geometrical properties of the rank$-k$ numerical hulls of normal matrices are investigated. A characterization of normal matrices whose rank$-1$ numerical hulls are equal to their numerical range is given. Moreover, using the extreme points of the numerical range, the higher rank numerical hulls of matrices of the form $A_1 oplus i A_2$, where $A_1$ and $A_2$ are Hermitian, are investigated. The higher rank numerical hulls of the basic circulant matrix are also studied.
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Journal title
volume 4 issue 1
pages 23- 32
publication date 2017-08-01
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