The boundary of the Krein space tracial numerical range, an algebraic approach ...

• Author(s): Bebiano, N. ; Nakazato, H. ; Nata, A. ; Providência, J. da
• Date: 2009
• Persistent ID: http://hdl.handle.net/10316/13644
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Numerical range; Inde nite inner product; J-Hermitian matrix; Non-interlacing eigenvalues
• Document Type: Preprint
• Language: English

Description

In this article, tracial numerical ranges associated with matrices in an inde nite inner product space are investigated. The boundary equations of these sets are obtained and the case of the boundary being a polygon is studied. As an application, a numerical algorithm for plotting the tracial numerical range of an arbitrary complex matrix, is presented. Our approach uses the elementary idea that the boundary may be traced by computing the supporting lines.