Czechoslovak Mathematical Journal, first online, pp. 1-9


A note on classes of structured matrices with elliptical type numerical range

Natália Bebiano, Susana Furtado

Received May 4, 2020.   Published online February 3, 2021.

Abstract:  We identify new classes of structured matrices whose numerical range is of the elliptical type, that is, an elliptical disk or the convex hull of elliptical disks.
Keywords:  tridiagonal matrix; antitridiagonal matrix; elliptical disk; numerical range
Classification MSC:  15A21, 15A60
DOI:  10.21136/CMJ.2021.0174-20

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Affiliations:   Natália Bebiano, Mathematics Center of the University of Coimbra, Mathematics Department, University of Coimbra, 3001-454 Coimbra, Portugal, e-mail: bebiano@mat.uc.pt; Susana Furtado (corresponding author), Center for Functional Analysis, Linear Structures and Applications, Faculty of Economics, University of Porto, Rua Dr. Roberto Frias, 4200-464 Porto Portugal, e-mail: sbf@fep.up.pt


 
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