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The transform considered in the paper integrates a function supported in the unit disk on the plane over all circles centered at the boundary of this disk. Such circular Radon transform arises in several contemporary imaging techniques, as…

General Mathematics · Mathematics 2007-05-23 Gaik Ambartsoumian , Peter Kuchment

We consider the problem of projecting a probability measure $\pi$ on a set $\mathcal{M}\_N$ of Radon measures. The projection is defined as a solution of the following variational problem:\begin{equation*}\inf\_{\mu\in \mathcal{M}\_N}…

Numerical Analysis · Mathematics 2015-09-02 Nicolas Chauffert , Philippe Ciuciu , Jonas Kahn , Pierre Weiss

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

In operator algebra theory, a conditional expectation is usually assumed to be a projection map onto a sub-algebra. In the paper, a further type of conditional expectation and an extension of the Lueders - von Neumann measurement to…

Mathematical Physics · Physics 2010-01-22 Gerd Niestegge

Given the joint distribution of two random variables $X,Y$ on some second countable locally compact Hausdorff space, we investigate the statistical approximation of the $L^2$-operator defined by $[Pf](x) := \mathbb{E}[ f(Y) \mid X = x ]$…

Statistics Theory · Mathematics 2023-08-08 Mattes Mollenhauer , Péter Koltai

We consider a family {P} of determinantal point processes arising in representation theory and random matrix theory. The processes live on the one-dimensional lattice and their correlation kernels correspond to projection operators in the…

Probability · Mathematics 2013-03-04 Grigori Olshanski

Recently, within the context of the phase space coherent state path integral quantisation of constrained systems, John Klauder introduced a reproducing kernel for gauge invariant physical states, which involves a projection operator onto…

High Energy Physics - Theory · Physics 2008-11-26 Jan Govaerts

In this paper, we introduce the spectral projection operators $\mathbb{P}_m$ on non-degenerate nilpotent Lie groups $\mathcal{N}$ of step two, associated to the joint spectrum of sub-Laplacian and derivatives in step two. We construct their…

Functional Analysis · Mathematics 2024-04-05 Qianqian Kang , Der-Chen Chang , Wei Wang

For any measurable set $E$ of a measure space $(X, \mu)$, let $P_E$ be the (orthogonal) projection on the Hilbert space $L^2(X, \mu)$ with the range $ran \, P_E = \{f \in L^2(X, \mu) : f = 0 \ \ a.e. \ on \ E^c\}$ that is called a standard…

Functional Analysis · Mathematics 2016-12-09 Roman Drnovšek

In this article we consider asymptotics for the spectral function of Schr\"odinger operators on the real line. Let $P:L^2(\mathbb{R})\to L^2(\mathbb{R})$ have the form $$ P:=-\tfrac{d^2}{dx^2}+W, $$ where $W$ is a self-adjoint first order…

Spectral Theory · Mathematics 2021-01-18 Jeffrey Galkowski

Given a compact manifold $ \mathcal{N} $ embedded into $ \mathbb{R}^{\nu} $ and a projection $ P $ that retracts $ \mathbb{R}^{\nu} $ except a singular set of codimension $ \ell $ onto $ \mathcal{N} $, we investigate the maximal range of…

Functional Analysis · Mathematics 2026-05-06 Antoine Detaille

The conical Radon transform is an integral transform that maps a given function $f$ to its integral over a conical surface. In this study, we invesgate the conical Radon transform with a fixed central axis and opening angle, considering the…

Functional Analysis · Mathematics 2024-09-23 Gihyeon Jeon

Let $(X,T^{1,0}X)$ be a compact orientable embeddable three dimensional strongly pseudoconvex CR manifold and let ${\rm P\,}$ be the associated CR Paneitz operator. In this paper, we show that (I) ${\rm P\,}$ is self-adjoint and ${\rm P\,}$…

Analysis of PDEs · Mathematics 2014-05-02 Chin-Yu Hsiao

Northern Illinois University in collaboration with Fermi National Accelerator Laboratory (FNAL) and Delhi University has been designing and building a proton CT scanner for applications in proton treatment planning. The Phase II proton CT…

The paper is devoted to the range description of the Radon type transform that averages a function over all spheres centered on a given sphere. Such transforms arise naturally in thermoacoustic tomography, a novel method of medical imaging.…

Analysis of PDEs · Mathematics 2011-10-04 Mark Agranovsky , David Finch , Peter Kuchment

The projective line over the (non-commutative) ring of two-by-two matrices with coefficients in GF(2) is found to fully accommodate the algebra of 15 operators - generalized Pauli matrices - characterizing two-qubit systems. The relevant…

Quantum Physics · Physics 2008-06-26 Metod Saniga , Michel Planat , Petr Pracna

Fixing the number of particles $N$, the quantum canonical ensemble imposes a constraint on the occupation numbers of single-particle states. The constraint particularly hampers the systematic calculation of the partition function and any…

Statistical Mechanics · Physics 2016-12-23 Wim Magnus , Fons Brosens

Uncertainties in the proton range in tissue during proton therapy limit the precision in treatment delivery. These uncertainties result in expanded treatment margins, thereby increasing radiation dose to healthy tissue. Real-time range…

Medical Physics · Physics 2018-10-17 Kristian Smeland Ytre-Hauge , Kyrre Skjerdal , John Mattingly , Ilker Meric

This paper focuses on random projection operators when the subspace of projection is estimated. We derive non-asymptotic upper bounds on the error between the projection onto the estimated subspace and the projection onto the underlying…

Statistics Theory · Mathematics 2026-03-31 Luca Castelli

Suppose $\lambda_1$ and $\lambda_2$ are infinitely divisible Radon measures on real Banach spaces $E_1$ and $E_2$, respectively and let $T:E_{1} \rightarrow E_{2}$ be a Borel measurable mapping so that $T(\lambda_1) * \rho = \lambda_2 $ for…

Probability · Mathematics 2014-08-13 David Applebaum , Jan van Neerven
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