English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Let A be an n× n normal matrix, whose numerical range NR[A] is a k -polygon. If a unit vector v ∈ W ⊆ Cn, with dimW = k and the point v∗Av ∈ IntNR[A], then NR[A] is circumscribed to NR[P∗AP], where P is an n× (k− 1) isometry of {span{v}}⊥ W → Cn, [1]. In this paper, we investigate an internal approximation of NR[A] by an increasing sequence of NR[Cs] of compressed matrices Cs = R∗s ARs, with R∗s Rs = Ik+s−1, s = 1,2, . . . ,n− k and additionally NR[A] is expressed as limit of numerical ranges of k -compressions of A. Mathematics subject classification (2000): 15A18, 15A60, 47A20.

Limited approximation of numerical range of normal matrix