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When considered as submanifolds of Euclidean space, the Riemannian geometry of the round sphere and the Clifford torus may be formulated in terms of Poisson algebraic expressions involving the embedding coordinates, and a central object is…

Quantum Algebra · Mathematics 2015-06-16 Joakim Arnlind

We extend the construction of generalized fixed point algebras to the setting of locally compact quantum groups - in the sense of Kustermans and Vaes - following the treatment of Marc Rieffel, Ruy Exel and Ralf Meyer in the group case. We…

Operator Algebras · Mathematics 2013-11-12 Alcides Buss

Based on the Lie theoretical methods of algebraic Fourier transformation, we classify in the case of generic values of inducing parameters the scalar singular vectors corresponding to the diagonal branching rules for scalar generalized…

Analysis of PDEs · Mathematics 2024-02-13 Petr Somberg

A broad class of contour gauges is shown to be determined by admissible contractions of the geometrical region considered and a suitable equivalence class of curves is defined. In the special case of magnetostatics, the relevant…

High Energy Physics - Theory · Physics 2009-10-31 L. Lukaszuk , E. Leader , A. Johansen

We study contractive projections, isometries, and real positive maps on algebras of operators on a Hilbert space. For example we find generalizations and variants of certain classical results on contractive projections on C*-algebras and…

Operator Algebras · Mathematics 2019-11-11 David P. Blecher , Matthew Neal

The Dunkl operators associated to a necessarily finite Coxeter group acting on a Euclidean space are generalized to any finite group using the techniques of non-commutative geometry, as introduced by the authors to view the usual Dunkl…

Mathematical Physics · Physics 2021-03-16 Micho Durdevich , Stephen Bruce Sontz

We obtain a characterization of the weighted inequalities for the Riesz transforms on weighted local Morrey spaces. The condition is sufficient for the boundedness on the same spaces of all Calder\'on-Zygmund operators suitably defined on…

Functional Analysis · Mathematics 2021-10-28 Javier Duoandikoetxea , Marcel Rosenthal

We obtain boundedness from a product of Lebesgue or Hardy spaces into Hardy spaces under suitable cancellation conditions for a large class of multilinear operators that includes the Coifman-Meyer class, sums of products of linear…

Functional Analysis · Mathematics 2017-02-09 Loukas Grafakos , Shohei Nakamura , Hanh Van Nguyen , Yoshihiro Sawano

The symplectic geometry of a broad class of generally covariant models is studied. The class is restricted so that the gauge group of the models coincides with the Bergmann-Komar group and the analysis can focus on the general covariance. A…

General Relativity and Quantum Cosmology · Physics 2009-10-31 P. Hajicek , J. Kijowski

This article shows that the approach to generalised curvature and torsion pioneered by Polacek and Siegel [1] is a generalisation of Cartan Geometry -- rendering latter natural from the point of view of O(d,d)-generalised geometry. We…

High Energy Physics - Theory · Physics 2024-09-19 Falk Hassler , Ondrej Hulik , David Osten

In this paper we study the embedding problem of an operator into a strongly continuous semigroup. We obtain characterizations for some classes of operators, namely composition operators and analytic Toeplitz operators on the Hardy space…

Functional Analysis · Mathematics 2025-02-19 Isabelle Chalendar , Romain Lebreton

In this note, we develop a parallel theory of the classical Sz.-Nagy--Foias dilation and model theory for a single contraction operator in the setting of pairs of \em{{$q$-commuting}} contraction operators for a unimodular complex number…

Functional Analysis · Mathematics 2025-11-19 Sourav Ghosh

Given a holomorphic self-map $\varphi$ of $\D$ (the open unit disc in $\mathbb{C}$), the composition operator $C_{\varphi} f = f \circ \varphi$, $f \in H^2(\mathbb{\D})$, defines a bounded linear operator on the Hardy space…

Functional Analysis · Mathematics 2021-08-13 P. Muthukumar , Jaydeb Sarkar

The goal of the present paper is to introduce and study noncommutative Hardy spaces associated with the regular $\Lambda$-polyball, to develop a functional calculus on noncommutative Hardy spaces for the completely non-coisometric (c.n.c.)…

Functional Analysis · Mathematics 2020-01-31 Gelu Popescu

Inspired by the spin geometry theorem, two operators are defined which measure angles in the quantum theory of geometry. One operator assigns a discrete angle to every pair of surfaces passing through a single vertex of a spin network. This…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Seth A. Major

We generalise the construction of fuzzy CP^N in a manner that allows us to access all noncommutative equivariant complex vector bundles over this space. We give a simplified construction of polarization tensors on S^2 that generalizes to…

High Energy Physics - Theory · Physics 2008-11-26 Brian P. Dolan , Idrish Huet , Sean Murray , Denjoe O'Connor

Let B be a unital C*-subalgebra of a unital C*-algebra A, so that A/B is an abstract operator space. We show how to realize A/B as a concrete operator space by means of a completely contractive map from A into the algebra of operators on a…

Operator Algebras · Mathematics 2014-06-12 Marc A. Rieffel

Well-known operations defined on a non-degenerate inner product vector space are extended to the case of a degenerate inner product. The main obstructions to the extension of these operations to the degenerate case are (1) the index…

Mathematical Physics · Physics 2011-12-30 Ovidiu Cristinel Stoica

The Schroedinger operators on the Newtonian space-time are defined in a way which make them independent on the class of inertial observers. In this picture the Schroedinger operators act not on functions on the space-time but on sections of…

Mathematical Physics · Physics 2011-11-22 Katarzyna Grabowska , Janusz Grabowski , Pawel Urbanski

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