Spectral variation conjecture for normal operators and differentiator compressions
Spectral variation conjecture for normal operators and differentiator compressions
Let be a normal operator on a complex Hilbert space of dimension . Let denote the radius of the smallest closed disk containing the spectrum of , let be the compression of to the orthogonal complement of a trace vector of , and let denote the spectral variation between and . The spectral variation conjecture. One has
and equality occurs if and only if either , or has simple eigenvalues and is a non-zero scalar operator. The claim reformulates the polynomial conjectures in terms of spectra of a normal operator and its compression. The source gives no resolution, so the conjecture remains open there.
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Sources & referencesView supporting material
Primary source
Julius Borcea, “Maximal and inextensible polynomials and the geometry of the spectra of normal operators”, arXiv:math/0309233 (2007).
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