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A group G is representable in a Banach space X if G is isomorphic to the group of isometries on X in some equivalent norm. We prove that a countable group G is representable in a separable real Banach space X in several general cases,…

Functional Analysis · Mathematics 2007-07-30 Valentin Ferenczi , Eloi Medina Galego

In this paper we give a various conditions for which the tuple $\mathcal{T} = (T_{1} , T_{2} , ... , T_{n})$ of commutative bounded linear operators on an infinite dimensional ( real , complex ) Banach space X is orbit reflexive. After we…

Functional Analysis · Mathematics 2018-12-19 Abdelaziz Tajmouati , Youness Zahouan

We study when diameter two properties pass down to subspaces. We obtain that the slice two property (respectively diameter two property, strong diameter two property) passes down from a Banach space $X$ to a subspace $Y$ whenever $Y$ is…

Functional Analysis · Mathematics 2017-02-22 Julio Becerra Guerrero , Ginés López-Pérez , Abraham Rueda Zoca

We consider the set of pairs of orthogonal vectors in Hilbert space, which is also called the cross because it is the union of the horizontal and vertical axes in the Euclidean plane when the underlying space is the real line. Crosses,…

Optimization and Control · Mathematics 2022-02-04 Heinz H. Bauschke , Manish Krishan Lal , Xianfu Wang

It is well known that the description of topological and geometric properties of bisectors in normed spaces is a non-trivial subject. In this paper we introduce the concept of bounded representation of bisectors in finite dimensional real…

Geometric Topology · Mathematics 2010-02-02 Á. G. Horváth , H. Martini

Associated with every separable Hilbert space $\mathcal{H}$ and a given localized frame, there exists a natural test function Banach space $\mathcal{H}^1$ and a Banach distribution space $\mathcal{H}^{\infty}$ so that $\mathcal{H}^1 \subset…

Functional Analysis · Mathematics 2025-02-12 Nikolas Hauschka , Peter Balazs , Lukas Köhldorfer

Let $X$ be a given Banach space and let $M$, $N$ be two orthogonal $X$-valued local martingales such that $N$ is weakly differentially subordinate to $M$. The paper contains the proof of the estimate $$ \mathbb E \Psi(N_t) \leq…

Functional Analysis · Mathematics 2019-07-03 Adam Osękowski , Ivan Yaroslavtsev

We show that if $1<p\neq 2<\infty$, then any isometry of the $p$-convexification of the combinatorial Banach space associated with a hereditary family of finite subsets of $\mathbb{N}$ containing the singletons is given by a signed…

Functional Analysis · Mathematics 2023-05-23 Micheline Fakhoury

This paper considers two commuting smooth transformations on a Banach space, and proves the sub-additivity of the measure theoretic entropies under mild conditions. Furthermore, some additional conditions are given for the equality of the…

Dynamical Systems · Mathematics 2025-07-31 ChiYi Luo , Yun Zhao

The notion of nonpositive curvature in Alexandrov's sense is extended to include p-uniformly convex Banach spaces. Infinite dimensional manifolds of semi-negative curvature with a p-uniformly convex tangent norm fall in this class on…

Differential Geometry · Mathematics 2014-02-26 Cristian Conde , Gabriel Larotonda

This paper generalizes results for alternate dual frames in Hilbert spaces on the situation of a Banach space. Additionally some properties of synthesys operator associated with alternate dual frame are investigated. The main result is that…

Functional Analysis · Mathematics 2011-11-01 Sergey Kreys

We determine that the deformation space of convex real projective structures, that is, projectively flat torsion-free connections with the geodesic convexity property on a compact 2-orbifold of negative Euler characteristic is homeomorphic…

Geometric Topology · Mathematics 2011-07-12 Suhyoung Choi , William Goldman

We provide new conditions under which the alternating projection sequence converges in norm for the convex feasibility problem where a linear subspace with finite codimension $N\geq 2$ and a lattice cone in a Hilbert space are considered.…

Optimization and Control · Mathematics 2024-12-16 Francesco Battistoni , Enrico Miglierina

We prove that if the group of isometries of C(X,E) is algebraically reflexive, then the group of n-isometries is also algebraically reflexive. Here, X is a compact Hausdorff space and E is a Banach space. As a corollary to this, we…

Functional Analysis · Mathematics 2012-05-28 A. B. Abubaker

We consider piecewise cone hyperbolic systems satisfying a bunching condition and we obtain a bound on the essential spectral radius of the associated weighted transfer operators acting on anisotropic Sobolev spaces. The bunching condition…

Dynamical Systems · Mathematics 2010-02-15 Viviane Baladi , Sebastien Gouezel

We prove that the norm of $X\widehat{\otimes}_\pi Y$ is SSD if either $X=\ell_p(I)$ for $p>2$ and $Y$ is a finite-dimensional Banach space such that the modulus of convexity is of power type $q<p$ (e.g. if $Y^*$ is a subspace of $L_q$) or…

Functional Analysis · Mathematics 2024-09-25 Abraham Rueda Zoca

Metric projection operators can be defined in similar wayin Hilbert and Banach spaces. At the same time, they differ signifitiantly in their properties. Metric projection operator in Hilbert space is a monotone and nonexpansive operator. It…

funct-an · Mathematics 2016-08-31 Ya. I. Alber

An algebra A of operators on a Banach space X is called strictly semi-transitive if for all non-zero x,y in X there exists an operator S in A such that Sx=y or Sy=x. We show that if A is norm-closed and strictly semi-transitive, then every…

Functional Analysis · Mathematics 2007-05-23 H. P. Rosenthal , V. G. Troitsky

We show that if $(X,d)$ is a metric space which admits a consistent convex geodesic bicombing, then we can construct a conical bicombing on $CB(X)$, the hyperspace of nonempty, closed, bounded, and convex subsets of $X$ (with the Hausdorff…

Metric Geometry · Mathematics 2022-03-24 Logan S. Fox

We introduce a norm-controlled notion of semiprojectivity for Banach lattices, requiring liftability of contractive lattice homomorphisms through inductive limits of closed ideals with arbitrarily small loss of norm control. Our main result…

Functional Analysis · Mathematics 2026-04-14 Tomasz Kania , Mariusz Niwiński