The k-rank numerical radii

2011/04/07 by Aretaki, Aikaterini, Maroulas, John
#15A60 #47A12 #FOS: Mathematics #Functional Analysis (math.FA)

paper · doi:10.48550/arxiv.1104.1338

Abstract

The k-rank numerical range Λ_k(A) is expressed via an intersection of a countable family of numerical ranges \F(M^*_νAM_ν)\_ν∈ℕ with respect to n× (n-k+1) isometries M_ν. This implication for Λ_k(A) provides further elaboration of the k-rank numerical radii of A.

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