Year: 2020
Type: article
Abstract: A complete description of 4-by-4 matrices αICDβI, with scalar 2-by-2 diagonal blocks, for which the numerical range is the convex hull of two non-concentric ellipses is given. This result is obtained by reduction to the leading special case in which C−D∗ also is a scalar multiple of the identity. In particular cases when in addition α−β is real or pure imaginary, the results take an especially simple form. An application to reciprocal matrices is provided.
Source: Linear and Multilinear Algebra
Authors: Titas Geryba, Ilya M. Spitkovsky
Institutions: Leiden University, New York University Abu Dhabi
Language: English
Topic: Matrix Theory and Algorithms
Subfield: Computational Theory and Mathematics
Field: Computer Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3081693423