牙齿 发表于 2025-3-26 22:23:56

https://doi.org/10.1007/978-3-642-60725-7We prove that any bounded component of the numerical range of a matrix polynomial .(λ) contains at least one eigenvalue of .(λ). Moreover, the set of corresponding Jordan chains is complete.

wangle 发表于 2025-3-27 01:17:10

The Sympatric Origin of Phytophagous InsectsThe perturbation of the multiplication operator in the space ..(0,1) by a Volterra operator with degenerate kernel is a particular case of the socalled “Friedrichs model”. We characterize the point spectrum of such a perturbation and establish a sharp result on the Lyapunov stability in the case that the kernel vanishes on the diagonal.

Insatiable 发表于 2025-3-27 05:33:05

D. Ebert,R. J. H. Payne,W. W. WeisserThe aim of the present paper is to compute the number of negative squares of certain functions, especially of some polynomials of several variables.

Protein 发表于 2025-3-27 11:44:53

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一回合 发表于 2025-3-27 16:14:17

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赏钱 发表于 2025-3-27 21:29:08

,On the defect of noncontractive operators in Kreĭn spaces: a new formula and some applications,We prove a formula for the defect of a noncontractive operator from one Krein space to another and give some applications of this notion to the study of the spectral properties of nondecreasing continuous or real analytic functions whose values are selfadjoint operators on a Hilbert space.

Bucket 发表于 2025-3-28 00:34:43

,Positive differential operators in the Krein space L2(ℝn),We characterize a class of indefinite partial differential operators which are similar to selfadjoint operators in the Hilbert space ..(ℝ.).

仔细阅读 发表于 2025-3-28 04:18:14

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事先无准备 发表于 2025-3-28 07:15:36

An analysis of the block structure of ,,-inner functions,This paper is aimed at analyzing of the canonical block structure of ..-inner functions. Inspired by papers of Arov and Dewilde/Dym , a concept of parametrization of ..-inner functions is developed.

Indolent 发表于 2025-3-28 13:29:34

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查看完整版本: Titlebook: Contributions to Operator Theory in Spaces with an Indefinite Metric; The Heinz Langer Ann Aalt Dijksma,Israel Gohberg,Reinhard Mennicken B