Some variations on the concept of the c-numerical range
Generalized numerical ranges of permanental compounds arising from quantum systems of bosons.
Interdependence of some problems arising in generalizing the Marcus-de Oliveira determinantal conjecture
Krein spaces numerical ranges and their computer generation.
A note on classes of structured matrices with elliptical type numerical range
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.
Computing the numerical range of Krein space operators
Consider the Hilbert space (H,〈• , •〉) equipped with the indefinite inner product[u,v]=v*J u,u,v∈ H, where J is an indefinite self-adjoint involution acting on H. The Krein space numerical range WJ(T) of an operator T acting on H is the set of all the values attained by the quadratic form [Tu,u], with u ∈H satisfying [u,u]=± 1. We develop, implement and test an alternative algorithm to compute WJ(T) in the finite dimensional case, constructing 2 by 2 matrix compressions of T and their easily determined...
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