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Related papers: Absolutely minimum attaining closed operators

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We define the concept of completely regular ordinary differential operators and give various criteria for operators to belong to this class. We give also criteria for Birkhof regularity of ordinary differential operators in terms of the…

Spectral Theory · Mathematics 2007-07-06 E. A. Shiryaev , A. A. Shkalikov

In this paper, we initiate the study of a new interrelation between linear ordinary differential operators and complex dynamics which we discuss in details in the simplest case of operators of order $1$. Namely, assuming that such an…

Dynamical Systems · Mathematics 2024-05-31 Per Alexandersson , Nils Hemmingsson , Dmitry Novikov , Boris Shapiro , Guillaume Tahar

We study order-to-weak continuous operators from an ordered Banach space to a normed space. It is proved that under rather mild conditions every order-to-weak continuous operator is bounded.

Functional Analysis · Mathematics 2026-03-12 Eduard Emelyanov

We introduce unbounded strongly irreducible operators and transitive operators. These operators are related to a certain class of indecomposable Hilbert representations of quivers on infinite-dimensional Hilbert spaces. We regard the theory…

Functional Analysis · Mathematics 2016-03-28 Masatoshi Enomoto , Yasuo Watatani

It is proved recently by Benamara-Nikolski that a contraction having finite defects and spectrum not filling in the closed unit disc, is similar to a normal operator if and only if it has the so-called linear resolvent growth property. We…

Spectral Theory · Mathematics 2007-05-23 Stanislav Kupin

We characterize inclusions of compact noncommutative convex sets with the property that every continuous affine function on the smaller set can be extended to a continuous affine function on the larger set with a uniform bound. As an…

Operator Algebras · Mathematics 2025-08-06 Adam Humeniuk , Matthew Kennedy , Nicholas Manor

In this paper, we introduce and study a new concept of unbounded order demi Dunford-Pettis operators. Namely, we investigate some properties for this new class of operators and we study its connection with other known operators, we also…

Functional Analysis · Mathematics 2024-05-24 Noufissa Hafidi , Jawad H'michane

The main goal of this note is to show that (not necessarily holomorphic) multipliers of a wide class of normed spaces of continuous functions over a connected Hausdorff topological space cannot attain their multiplier norms, unless they are…

Functional Analysis · Mathematics 2020-08-11 Eugene Bilokopytov

We obtain exhaustive results and treat in a unified way the question of boundedness, compactness, and weak compactness of composition operators from the Bloch space into any space from a large family of conformally invariant spaces that…

Functional Analysis · Mathematics 2016-11-07 Manuel D. Contreras , Santiago Diaz-Madrigal , Dragan Vukotic

We introduce unbounded multipliers on operator spaces. These multipliers generalize both, regular operators on Hilbert C*-modules and (bounded) multipliers on operator spaces.

Operator Algebras · Mathematics 2010-07-23 Hendrik Schlieter , Wend Werner

We give different types of new characterizations for the boundedness and essential norms of generalized weighted composition operators between Zygmund type spaces. Consequently, we obtain new characterizations for the compactness of such…

Functional Analysis · Mathematics 2019-04-01 Mostafa Hassanlou , Amir H. Sanatpour

The local boundedness of classes of operators is analyzed on different subsets directly related to their Fitzpatrick functions and characterizations of the topological vector spaces for which that local boundedness holds is given in terms…

Functional Analysis · Mathematics 2012-07-13 M. D. Voisei

We prove some unconditional cases of the Existential Closedness problem for the modular $j$-function. For this, we show that for any finitely generated field we can find a "convenient" set of generators. This is done by showing that in any…

Logic · Mathematics 2022-10-06 Vahagn Aslanyan , Sebastian Eterović , Jonathan Kirby

We look at spaces of infinite-by-infinite matrices, and consider closed subsets that are stable under simultaneous row and column operations. We prove that up to symmetry, any of these closed subsets is defined by finitely many equations.

Algebraic Geometry · Mathematics 2016-02-26 Rob Eggermont

In this paper, we establish results about operators similar to their adjoints. This is carried out in the setting of bounded and also unbounded operators on a Hilbert space. Among the results, we prove that an unbounded closed operator…

Functional Analysis · Mathematics 2014-06-02 Souheyb Dehimi , Mohammed Hichem Mortad

We introduce a class of operators on abstract measure spaces, which unifies the Calder\'on-Zygmund operators on spaces of homogeneous type, the maximal functions and the martingale transforms. We prove that such operators can be dominated…

Classical Analysis and ODEs · Mathematics 2022-11-07 Grigori A. Karagulyan

Fundamental properties of unbounded composition operators in $L^2$-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal. Composition…

Functional Analysis · Mathematics 2013-10-15 Piotr Budzyński , Zenon Jan Jabłoński , Il Bong Jung , Jan Stochel

We consider the global Morrey-type spaces with variable exponents and general function defining these spaces. In the case of unbounded sets, we prove boundedness of the Hardy-Littlewood maximal operator, potential type operator in these…

Functional Analysis · Mathematics 2021-06-07 Nurzhan A. Bokayev , Zhomart M. Onerbek

We introduce a class of linear bounded invertible operators on Banach spaces, called shift operators, which comprises weighted backward shifts and models finite products of weighted backward shifts and dissipative composition operators. We…

Dynamical Systems · Mathematics 2024-07-31 Maria Carvalho , Udayan B. Darji , Paulo Varandas

In this paper, using the concept of unbounded absolute weak convergence ($uaw$-convergence, for short) in a Banach lattice, we define two classes of continuous operators, named $uaw$-Dunford-Pettis and $uaw$-compact operators. We…

Functional Analysis · Mathematics 2019-02-28 Nazife Erkursun Ozcan , Niyazi Anil Gezer , Omid Zabeti