# Some results on the polynomial numerical hulls of matrices

Document Type : Research Paper

Authors

1 Department of Mathematics, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.

2 Department of Mathematics, Shahid Bahonar University of Kerman, Kerman, Iran.

Abstract

In this note we characterize polynomial numerical hulls of matrices $A in M_n$ such that
$A^2$ is Hermitian. Also, we consider normal matrices $A in M_n$ whose $k^{th}$ power are semidefinite. For such matrices
we show that $V^k(A)=sigma(A)$.

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### History

• Receive Date: 06 March 2011
• Revise Date: 29 May 2012
• Accept Date: 29 May 2012