The elliptical range theorem for the conformal range
Spectral Theory
2026-03-26 v1
Abstract
The conformal range (or the real Davis--Wielandt shell), which is a particular planar projection of the Davis--Wielandt shell, can be considered as the hyperbolic version of the numerical range; i. e. it is a ``field of values'' which can be interpreted as a subset of the asymptotically closed hyperbolic plane. Here we explain the analogue of the elliptical range theorem of complex matrices for the conformal range.
Keywords
Cite
@article{arxiv.2603.23545,
title = {The elliptical range theorem for the conformal range},
author = {Gyula Lakos},
journal= {arXiv preprint arXiv:2603.23545},
year = {2026}
}