Displaying similar documents to “A note on classes of structured matrices with elliptical type numerical range”

On numerical range of sp(2n, C)

Wen Yan, Jicheng Tao, Zhao Lu (2016)

Special Matrices

Similarity:

In this paper we studied the classical numerical range of matrices in sp(2n, C). We obtained some result on the relationship between the numerical range of a matrix in and that [...] of its diagonal block, the singular values of its off-diagonal block A2.

Computing the numerical range of Krein space operators

Natalia Bebiano, J. da Providência, A. Nata, J.P. da Providência (2015)

Open Mathematics

Similarity:

Consider the Hilbert space (H,〈• , •〉) equipped with the indefinite inner product[u,v]=v*J u,u,v∈ H, where J is an indefinite self-adjoint involution acting on H. The Krein space numerical range WJ(T) of an operator T acting on H is the set of all the values attained by the quadratic form [Tu,u], with u ∈H satisfying [u,u]=± 1. We develop, implement and test an alternative algorithm to compute WJ(T) in the finite dimensional case, constructing 2 by 2 matrix compressions of T and their...

Numerical index with respect to an operator

Mohammad Ali Ardalani (2014)

Studia Mathematica

Similarity:

We introduce new concepts of numerical range and numerical radius of one operator with respect to another one, which generalize in a natural way the known concepts of numerical range and numerical radius. We study basic properties of these new concepts and present some examples.

Numerical radius inequalities for 2 × 2 operator matrices

Omar Hirzallah, Fuad Kittaneh, Khalid Shebrawi (2012)

Studia Mathematica

Similarity:

We derive several numerical radius inequalities for 2 × 2 operator matrices. Numerical radius inequalities for sums and products of operators are given. Applications of our inequalities are also provided.