English
Related papers

Related papers: Isometries and Hermitian Operators on Zygmund spac…

200 papers

This paper demonstrates the power of the calculus developed in the two previous parts of the series for all real forms of the almost Hermitian symmetric structures on smooth manifolds, including e.g. conformal Riemannian and almost…

Differential Geometry · Mathematics 2007-05-23 Andreas Cap , Jan Slovak , Vladimir Soucek

In this paper, we study the differentiation operator acting on discrete function spaces; that is spaces of functions defined on an infinite rooted tree. We discuss, through its connection with composition operators, the boundedness and…

Functional Analysis · Mathematics 2022-07-26 Robert F. Allen , Colin M. Jackson

It is well known that an (in general, non-commutative) set of non-Hermitian operators $\Lambda_j$ with real eigenvalues need not necessarily represent observables. We describe a specific class of quantum models in which these operators plus…

Quantum Physics · Physics 2022-08-02 Miloslav Znojil

In Bergman and Dirichlet spaces, the shift operator is not an isometry, but it is a left invertible operator. In this paper we give conditions on the left invertible operators such that a operator version, in the sense of Rosenblum and…

Functional Analysis · Mathematics 2017-04-14 Laura Gavruta

We study the description of semicommutative Hardy spaces in terms of molecules. We use this characterization to obtain $\mathrm{H}_1^c - \mathrm{H}_1^c$ estimates for Calder\'on-Zygmund operators with kernels with values in a semifinite von…

Functional Analysis · Mathematics 2025-09-03 Antonio Ismael Cano-Mármol

Corresponding to any $(m-1)$-tuple of semi-spectral measures on the unit circle, a weighted Dirichlet-type space is introduced and studied. We prove that the operator of multiplication by the coordinate function on these weighted…

Functional Analysis · Mathematics 2022-07-07 S. Ghara , R. Gupta , Md. R. Reza

We study compact operators on the Bergman space of the Thullen domain defined by $\{(z_1,z_2)\in \mathbb C^2: |z_1|^{2p}+|z_2|^2<1\}$ with $p>0$ and $p\neq 1$. The domain need not be smooth nor have a transitive automorphism group. We give…

Complex Variables · Mathematics 2018-10-16 Zhenghui Huo , Brett D. Wick

The paper is devoted to the study of geodesic orbit Riemannian spaces that could be characterize by the property that any geodesic is an orbit of a 1-parameter group of isometries. The main result is the classification of compact simply…

Differential Geometry · Mathematics 2020-05-19 Zhiqi Chen , Yu. G. Nikonorov

We define naturally Hermite-Lorentz metrics on almost-complex manifolds as special case of pseudo-Riemannian metrics compatible with the almost complex structure. We study their isometry groups.

Differential Geometry · Mathematics 2017-01-03 Ali Ben-Ahmed , Abdelghani Zeghib

In this article we study different aspects of Hermitian operators applying the concept of positive decompositions. On the one hand, we characterize the positivity of an Hermitian operator by means of a norm condition where the factors of…

Functional Analysis · Mathematics 2024-12-31 Guillermina Fongi , María Celeste Gonzalez

We give a generalization of the Hodge operator to spaces $(V,h)$ endowed with a hermitian or symmetric bilinear form $h$ over arbitrary fields, including the characteristic two case. Suitable exterior powers of $V$ become free modules over…

Group Theory · Mathematics 2024-10-15 Linus Kramer , Markus J. Stroppel

Differentiations of operator algebras over non-archimedean spherically complete fields are investigated. Theorems about a differentiation being internal are demonstrated.

Functional Analysis · Mathematics 2012-10-09 S. V. Ludkovsky

In this article, we characterize the bounded and the compact multiplication operators between distinct iterated logarithmic Lipschitz spaces, and between the Lipschitz space and an iterated logarithmic Lipschitz space of an infinite tree.…

Functional Analysis · Mathematics 2022-07-26 Robert F. Allen , Flavia Colonna , Andrew Prudhom

We reconsider studies of Toeplitz operators on function spaces (the weighted Bergman space, the generalized derivative Hardy space) and the H-Toeplitz operators on the Bergman space. Past studies have considered the presence or absence of…

Functional Analysis · Mathematics 2024-09-20 Chafiq Benhida , George R. Exner , Ji Eun Lee , Jongrak Lee

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

The aim of the present article is to give an introduction to the concept of quasi-unitary equivalence and to define several (pseudo-)metrics on the space of self-adjoint operators acting possibly in different Hilbert spaces. As some of the…

Functional Analysis · Mathematics 2025-04-30 Olaf Post , Jan Simmer

The aim of the present paper is, firstly we study the concepts of (m, (q_1, ..., q_d))- partial isometries on a Hilbert space, secondly, we introduce the notion of m- invertibility of tuples of operators as a natural generalization of the…

Functional Analysis · Mathematics 2016-03-01 Ould Ahmed Mahmoud Sid Ahmed

We study the varieties of invariant totally geodesic submanifolds of isometries of the spherical, Euclidean and hyperbolic spaces in each finite dimension. We show that the dimensions of the connected components of these varieties determine…

Differential Geometry · Mathematics 2016-10-13 Joana Cirici

We determine fusion rules (dimensions of the space of intertwining operators) among simple modules for the vertex operator algebra obtained as an even part of the symplectic fermionic vertex operator superalgebra. By using these fusion…

Quantum Algebra · Mathematics 2011-08-10 Toshiyuki Abe , Yusuke Arike

In our companion paper (S.N. Chandler Wilde, D.P. Hewett, A. Moiola, Sobolev spaces on non-Lipschitz subsets of $\mathbb{R}^n$ with application to boundary integral equations on fractal screens, 2016) we studied a number of different…

Functional Analysis · Mathematics 2022-08-29 David P. Hewett , Andrea Moiola