Vali-e-Asr university of RafsanjanWavelet and Linear Algebra2383-19364120170801On higher rank numerical hulls of normal matrices23322336710.22072/wala.2017.47123.1080ENGolamrezaAghamollaeiDepartment of Pure Mathematics, Faculty of Mathematics and Computer, Shahid Bahonar University of Kerman, Kerman, Islamic Republic of IranSharifehRezagholiDepartment of Mathematics, Payame Noor University (PNU) ;Tehran; Islamic Republic of Iran.Journal Article20160811In 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.https://wala.vru.ac.ir/article_23367_ebbd946a37c2e6eee2b03af2d07bdd99.pdf