The Property of Kippenhahn Curves of Hadamard Products and Applications

摘要

In this paper, and will denote reducible companion matrices. we combine the Kronecker product, Hadamard product with numerical rang of matrices, discuss the relations between the Kronecker product, Hadamard product with numerical rang of matrices, and illustrate that the kippenhahn curve consists of consists of one ellipse whose foci are and axis has a length .