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Related papers: Non-Archimedean Normal Operators

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In this paper, we introduce and study a new classes of operators, named AM-unbounded norm compact operators. We study the the basic properties of the new operator and we investigate the lattice-order and topology property of the operator…

Functional Analysis · Mathematics 2019-10-07 Wang Zhangjun , Chen Zili , Chen Jinxi

The basic results for nonlinear operators are given. These results include nonlinear versions of classical uniform boundedness theorem and Hahn-Banach theorem. Furthermore, the mappings from a metrizable space into another normed space can…

Functional Analysis · Mathematics 2019-05-28 Wen Hsiang Wei

We furnish a simple way of constructing an unbounded closed linear operator in a complex Banach space, whose spectrum is an arbitrary nonempty closed, in particular compact, subset of the complex plane.

Functional Analysis · Mathematics 2021-07-26 Marat V. Markin

This article introduces classes of normal and unitary operators on smooth Banach spaces, providing extensions of the classical notions of normal and unitary operators from Hilbert spaces to the smooth Banach space setting. The proposed…

Functional Analysis · Mathematics 2026-05-18 Mohammed Shameem , Deepesh K P

We establish criteria for the stability of the essential spectrum for unbounded operators acting in Banach modules. The applications cover operators acting on sections of vector fiber bundles over non-smooth manifolds or locally compact…

Spectral Theory · Mathematics 2007-05-23 Vladimir Georgescu , Sylvain Golenia

Affiliated and normal operators in octonion Hilbert spaces are studied. Theorems about their properties and of related algebras are demonstrated. Spectra of unbounded normal operators are investigated.

Functional Analysis · Mathematics 2018-12-18 S. V. Ludkovsky

In the paper we extend the spectral invariance of pseudodifferential operators acting on (non-weighted) classical modulation spaces to allow the Lebesgue exponents to be smaller than one. These spaces occur naturally in approximation theory…

Functional Analysis · Mathematics 2023-05-29 Karlheinz Gröchenig , Christine Pfeuffer , Joachim Toft

We prove several abstract results giving general conditions under which subspaces of linear or multilinear operators on Banach spaces or Banach lattices are closed. Each of these abstract results is followed by concrete applications,…

Functional Analysis · Mathematics 2026-05-25 Geraldo Botelho , Ariel Monção

The non-Archimedean spectral theory and spectral integration is developed. The analog of the Stone theorem is proved. Applications are considered for algebras of operators.

Spectral Theory · Mathematics 2018-12-18 S. Ludkovsky , B. Diarra

We study the notion of recurrence and some of its variations for linear operators acting on Banach spaces. We characterize recurrence for several classes of linear operators such as weighted shifts, composition operators and multiplication…

Functional Analysis · Mathematics 2015-09-01 George Costakis , Antonios Manoussos , Ioannis Parissis

We study the Spectral Analysis for a class of bounded linear operators T = D + F in a non Archimedean Hilbert space E, where D is a diagonal linear operator and where F is a finite rank linear operator. In this study of the Spectral…

Functional Analysis · Mathematics 2022-11-30 Teylama Miabey

We generalize an important class of Banach spaces, namely the $M$-embedded Banach spaces, to the non-commutative setting of operator spaces. The one-sided $M$-embedded operator spaces are the operator spaces which are one-sided $M$-ideals…

Operator Algebras · Mathematics 2009-07-01 Sonia Sharma

We study approximately orthogonality (in the sense of Dragomir) preserving and reversing operators. We show that for some orthogonality notations, an operator defined from a finite-dimensional Banach space to a normed linear space is…

Functional Analysis · Mathematics 2025-12-11 Divya Khurana

A new approach to normal operators in real Hilbert spaces is discussed, and a spectral representation is obtained, derived directly from the complex case. The results are then applied to quaternionic normal operators, regarded as a special…

Functional Analysis · Mathematics 2025-07-28 Florian-Horia Vasilescu

In this paper we describe the surjective linear isometries on a vector valued little Bloch space with range space a strictly convex and smooth complex Banach space. We also describe the hermitian operators and the generalized bi-circular…

Functional Analysis · Mathematics 2014-09-19 Fernanda Botelho , James Jamison

We introduce a class of (tuples of commuting) unbounded operators on a Banach space, admitting smooth functional calculi, that contains all operators of Helffer-Sj\"ostrand type and is closed under the action of smooth proper mappings.…

Spectral Theory · Mathematics 2016-08-16 Mats Andersson , Håkan Samuelsson , Sebastian Sandberg

In this paper we explore the properties of a bounded linear operator defined on a Banach space, in light of operator norm attainment. Using Birkhoff-James orthogonality techniques, we give a necessary condition for a bounded linear operator…

Functional Analysis · Mathematics 2016-08-03 Debmalya Sain

In this survey, we shall present characterizations of some distinguished classes of Hilbertian bounded linear operators (namely, normal operators, selfadjoint operators, and unitary operators) in terms of operator inequalities related to…

Functional Analysis · Mathematics 2020-07-03 Ameur Seddik

We introduce and study non-Archimedean analogs of the operators of unilateral shift and backward shift playing crucial roles in the classical theory of nonselfadjoint operators. In particular, we find various functional models of these…

Functional Analysis · Mathematics 2010-06-02 Anatoly N. Kochubei

In \cite{Os} a general spectral approximation theory was developed for compact operators on a Banach space which does not require that the operators be self-adjoint and also provides a first order correction term. Here we extend some of the…

Mathematical Physics · Physics 2016-01-20 Shari Moskow