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We present commuting projection operators on de Rham sequences of two-dimensional multipatch spaces with local tensor-product parametrization and non-matching interfaces. Our construction yields projection operators which are local and…

Numerical Analysis · Mathematics 2023-05-30 Martin Campos Pinto , Frederik Schnack

We explicitly describe the Haagerup and the Kosaki non-commutative $L^p$-spaces associated with a tensor product von Neumann algebra $M_1\bar{\otimes}M_2$ in terms of those associated with $M_i$ and usual tensor products of unbounded…

Operator Algebras · Mathematics 2024-07-09 Shinya Kato , Yoshimichi Ueda

We characterize operators $T=PQ$ ($P,Q$ orthogonal projections in a Hilbert space $H$) which have a singular value decomposition. A spatial characterizations is given: this condition occurs if and only if there exist orthonormal bases…

Functional Analysis · Mathematics 2017-06-19 Esteban Andruchow , Gustavo Corach

We study the structure of strictly singular non-compact operators between $L_p$ spaces. Answering a question raised in [Adv. Math. 316 (2017), 667-690], it is shown that there exist operators $T$, for which the set of points…

Functional Analysis · Mathematics 2020-01-28 Francisco L. Hernández , Evgeny M. Semenov , Pedro Tradacete

We prove that the space of contractible simple loops of a given fixed area in any compact oriented surface has infinite diameter as a homogeneous space of the group of area-preserving diffeomorphisms endowed with the $L^p$-metric. As a…

Geometric Topology · Mathematics 2026-05-06 Michael Brandenbursky , Egor Shelukhin

Let X be an L_1-predual space and let K be a countable linearly independent subset of the extreme points of its closed dual ball. It is shown that if the norm-closed linear span Y of K is w^*-closed in X^*, then Y is the range of a…

Functional Analysis · Mathematics 2007-05-23 Ioannis Gasparis

In this paper we consider unbounded weighted conditional type operators on the space Lp, we give some conditions under which they are densely defined and we obtain a dense subset of the domain. Also, we get that a WCT operator is continuous…

Functional Analysis · Mathematics 2015-12-25 Yousef Estaremi

For every H-space $X$ the set of homotopy classes $[X,X]$ possesses a natural algebraic structure of a loop near-ring. Albeit one cannot say much about general loop near-rings, it turns out that those that arise from H-spaces are…

Algebraic Topology · Mathematics 2016-12-21 Damir Franetič , Petar Pavešić

For $p \in [1, \infty)$, we generalize the concept of classical spectral triples by extending the framework from Hilbert spaces to $L^p$-spaces, and from C*-algebras to $L^p$-operator algebras. In addition, we define an $L^p$-spectral…

Functional Analysis · Mathematics 2026-01-12 Alonso Delfín , Carla Farsi , Judith Packer

We will introduce twisted cycles and their associated regulators to cohomology. We prove the conjecture that this regulator is surjective for a general smooth projective surface. We construct indecomposable twisted cycles on elliptic…

Algebraic Geometry · Mathematics 2024-02-23 Karim Mansour

Boundedness for a class of projection operators, which includes the coordinate projections, on matrix weighted $L^p$-spaces is completely characterised in terms of simple scalar conditions. Using the projection result, sufficient…

Functional Analysis · Mathematics 2015-03-09 Morten Nielsen , Morten Grud Rasmussen

Let $T\colon L^p({\mathcal M})\to L^p({\mathcal N})$ be a bounded operator between two noncommutative $L^p$-spaces, $1\leq p<\infty$. We say that $T$ is $\ell^1$-bounded (resp. $\ell^1$-contractive) if $T\otimes I_{\ell^1}$ extends to a…

Operator Algebras · Mathematics 2021-06-22 Christian Le Merdy , Safoura Zadeh

Although the Bergman projection operator $\mathbf{B}_{\Omega}$ is defined on $L^2(\Omega)$, its behavior on other $L^p(\Omega)$ spaces for $p\not =2$ is an active research area. We survey some of the recent results on $L^p$ estimates on the…

Complex Variables · Mathematics 2020-05-19 Yunus E. Zeytuncu

The paper makes the first steps into the study of extensions ("twisted sums") of noncommutative $L^p$-spaces regarded as Banach modules over the underlying von Neumann algebra $\mathcal M$. Our approach combines Kalton's description of…

Operator Algebras · Mathematics 2016-02-02 Félix Cabello Sánchez , Jesús M. F. Castillo , Stanislaw Goldstein , Jesús Suárez

We prove an analogue of the classical Davis' decomposition for martingales in noncommutative L_p-spaces, involving the square functions. We also determine the dual space of the noncommutative conditioned Hardy space \h_1. We further extend…

Operator Algebras · Mathematics 2014-02-26 Mathilde Perrin

In this paper we present a result concerning locally contractive maps defined on subsets of perfect Polish ultrametric spaces (i.e. separable complete ultrametric spaces). Specifically, we show that a perfect compact ultrametric space…

Dynamical Systems · Mathematics 2015-05-04 Francis George

Let $1\leq p<\infty$ and let $T\colon L^p({\mathcal M})\to L^p({\mathcal N})$ be a bounded map between noncommutative $L^p$-spaces. If $T$ is bijective and separating (i.e., for any $x,y\in L^p({\mathcal M})$ such that $x^*y=xy^*=0$, we…

Operator Algebras · Mathematics 2021-04-19 Christian Le Merdy , Safoura Zadeh

In this paper, we study the boundedness, compactness and Schatten class membership of composition operators on the weighted $L^{p}$-space of a tree $L^{p}_{\lambda}(T)$ with $1\leq p <\infty$.

Functional Analysis · Mathematics 2023-03-21 Han Xu , Xiaoyan Zhang

We initiate and study the theory of ``real decomposable maps" between real operator systems. Formally, this is new even in the complex case, which hitherto has restricted itself to the case where the systems are complex C*-algebras. We…

Operator Algebras · Mathematics 2026-05-11 David P. Blecher , Christiaan H. Pretorius

We study embeddings of $L^p$-operator algebras arising from (twisted) \'etale groupoids, with particular emphasis on rigidity phenomena for $p\neq 2$. Our methods rely on a detailed analysis of core normalizers and their functorial behavior…

Functional Analysis · Mathematics 2026-01-22 Eusebio Gardella , Jan Gundelach