Abstract
By definition, reciprocal matrices are tridiagonal n-by-n matrices A with constant main diagonal and such that ai,i+1ai+1,i= 1 for i = 1,..., n - 1. We establish some properties of the numerical range generating curves C(A) (also called Kippenhahn curves) of such matrices, in particular concerning the location of their elliptical components. For n ≤ 6, in particular, we describe completely the cases when C(A) consist entirely of ellipses. As a corollary, we also provide a complete description of higher rank numerical ranges when these criteria are met.
Original language | English (US) |
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Pages (from-to) | 117-130 |
Number of pages | 14 |
Journal | Special Matrices |
Volume | 10 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1 2022 |
Keywords
- Kippenhahn curve
- Numerical range
- Reciprocal matrix
ASJC Scopus subject areas
- Algebra and Number Theory
- Geometry and Topology