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The aim of this paper is to establish a strong convergence theorem for a strongly nonexpansive sequence in a Banach space. We also deal with some applications of the convergence theorem.

Functional Analysis · Mathematics 2025-09-17 Koji Aoyama , Masashi Toyoda

This paper deals with study of Birkhoff-James orthogonality of a linear operator to a subspace of operators defined between arbitrary Banach spaces. In case the domain space is reflexive and the subspace is finite dimensional we obtain a…

Functional Analysis · Mathematics 2019-12-10 Arpita Mal , Kallol Paul

Given an arbitrary finite set of data F= {f_1,..., f_m} in L2(Rd) we prove the existence and show how to construct a "small shift invariant space" that is "closest" to the data F over certain class of closed subspaces of L2(Rd). The…

Functional Analysis · Mathematics 2019-01-09 Carlos Cabrelli , Carolina A. Mosquera

All most all the function spaces over real or complex domains and spaces of sequences, that arise in practice as examples of normed complete linear spaces (Banach spaces), are reflexive. These Banach spaces are dual to their respective…

General Mathematics · Mathematics 2022-03-01 Michael Oser Rabin , Duggirala Ravi

We consider the nonstationary iterated Tikhonov regularization in Banach spaces which defines the iterates via minimization problems with uniformly convex penalty term. The penalty term is allowed to be non-smooth to include $L^1$ and total…

Numerical Analysis · Mathematics 2014-01-21 Qinian Jin , Min Zhong

There has been a long-standing conjecture in Banach algebra that every amenable operator is similar to a normal operator. In this paper, we study the structure of amenable operators on Hilbert spaces. At first, we show that the conjecture…

Functional Analysis · Mathematics 2010-09-01 Luo Yi Shi , Yu Jing Wu , You Qing Ji

We construct a Banach space satisfying that the nearest point map (also called proximity mapping or metric projection) onto any compact and convex subset is continuous but not uniformly continuous. The space we construct is locally…

Functional Analysis · Mathematics 2024-02-08 Rubén Medina , Andrés Quilis

In a wide class of weighted Bergman spaces, we construct invertible non-cyclic elements. These are then used to produce z-invariant subspaces of index higher than one. In addition, these elements generate nontrivial bilaterally invariant…

Functional Analysis · Mathematics 2007-05-23 Alexander Borichev , Hakan Hedenmalm , Alexander Volberg

We construct a reflexive Banach space $X$ with a subspace isometric to $X$, which is not complemented in $X$.

Functional Analysis · Mathematics 2023-09-28 Anna Pelczar-Barwacz

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

In this article we obtain some positive results about the existence of a common nontrivial invariant subspace for $N$-tuples of not necessarily commuting operators on Banach spaces with a Schauder basis. The concept of joint quasinilpotence…

Functional Analysis · Mathematics 2007-05-23 A Fernández Valles

We show that if a nonscalar operator on a separable Hilbert space has a nontrivial invariant subspace, then it has also a nontrivial hyperinvariant subspace. Thus the hyperinvariant subspace problem is equivalent to the invariant subspace…

Functional Analysis · Mathematics 2025-04-01 László Kérchy , Carl Pearcy

This paper introduces an inner product on chain complexes of finite simplicial complexes that is well-adapted to the harmonic study of subdivisions. Its definition utilizes a decomposition of the chain spaces that suggests a sequence of…

Geometric Topology · Mathematics 2008-07-29 Jer-Chin Chuang

Arbitrary operator A on a Banach space X which is the generator of C_0-group with certain growth condition at infinity is considered. The relationship between its exponential type entire vectors and its spectral subspaces is found. Inverse…

Functional Analysis · Mathematics 2011-03-11 S. Torba

This article proposed a new approach to the determination of the spectrum for nonlinear continuous operators in the Banach spaces and using it investigated the spectrum of some classes of operators. Here shows that in nonlinear operators…

Functional Analysis · Mathematics 2022-01-10 Kamal N. Soltanov

We introduce and study the following modified version of the Invariant Subspace Problem: whether every operator T on a Banach space has an almost invariant half-space, that is, a subspace Y of infinite dimension and infinite codimension…

Functional Analysis · Mathematics 2009-01-08 George Androulakis , Alexey I. Popov , Adi Tcaciuc , Vladimir G. Troitsky

In this paper, we obtain a minimax theorem by means of which, in turn, we prove the following result: Let $E$ be an infinite-dimensional reflexive real Banach space, $T:E\to E$ a non-zero compact linear operator, $\varphi:E\to {\bf R}$ a…

Functional Analysis · Mathematics 2015-09-09 Biagio Ricceri

Let $T:X\to X$ be a linear power bounded operator on Banach space. Let $X_0$ is a subspace of vectors tending to zero under iterating of $T$. We prove that if $X_0$ is not equal to $X$ then there exists $\lambda$ in Sp(T) such that, for…

Functional Analysis · Mathematics 2010-05-02 K. V. Storozhuk

It is shown that if the Deddens algebra ${\mathcal D}_T$ associated with a quasinilpotent operator $T$ on a complex Banach space is closed and localizing then $T$ has a nontrivial closed hyperinvariant subspace.

Functional Analysis · Mathematics 2014-03-21 Miguel Lacruz

A Banach space X is superreflexive if each Banach space Y that is finitely representable in X is reflexive. Superreflexivity is known to be equivalent to J-convexity and to the non-existence of uniformly bounded factorizations of the…

Functional Analysis · Mathematics 2016-09-07 Joerg Wenzel