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Let $\mR$ be the restriction of the spherical Radon transform to the set of spheres centered on a hypersurface $\mS$. We study the inversion of $\mR$ by a closed-form formula. We approach the problem by studying an oscillatory integral,…

Classical Analysis and ODEs · Mathematics 2013-07-11 Linh V. Nguyen

Regularized methods have been widely applied to system identification problems without known model structures. This paper proposes an infinite-dimensional sparse learning algorithm based on atomic norm regularization. Atomic norm…

Systems and Control · Electrical Eng. & Systems 2023-03-20 Mingzhou Yin , Mehmet Tolga Akan , Andrea Iannelli , Roy S. Smith

We find sharp conditions for the maximal operator associated with generalized spherical mean Radon transform on radial functions $M^{\a,\b}_t$ to be bounded on power weighted Lebesgue spaces. Moreover, we also obtain the corresponding…

Classical Analysis and ODEs · Mathematics 2024-08-09 Adam Nowak , Luz Roncal , Tomasz Z. Szarek

We show that if $f$ is locally in $L\log\log L$ then the lacunary spherical means converge almost everywhere. The argument given here is a model case for more general results on singular maximal functions and Radon transforms (see ref. 6).

Classical Analysis and ODEs · Mathematics 2010-03-15 Andreas Seeger , Terence Tao , James Wright

Sparse reconstruction approaches using the re-weighted l1-penalty have been shown, both empirically and theoretically, to provide a significant improvement in recovering sparse signals in comparison to the l1-relaxation. However, numerical…

Machine Learning · Statistics 2013-12-06 Dmitry Malioutov , Aleksandr Aravkin

In this paper we deal with lacunary and full versions of the spherical maximal function on the Heisenberg group $\mathbb{H}^n$, for $n\ge 2$. By suitable adaptation of an approach developed by M. Lacey in the Euclidean case, we obtain…

Classical Analysis and ODEs · Mathematics 2021-03-12 S. Bagchi , S. Hait , L. Roncal , S. Thangavelu

A linear method for inverting noisy observations of the Radon transform is developed based on decomposition systems (needlets) with rapidly decaying elements induced by the Radon transform SVD basis. Upper bounds of the risk of the…

Statistics Theory · Mathematics 2011-11-04 Gérard Kerkyacharian , George Kyriazis , Erwan Le Pennec , Pencho Petrushev , Dominique Picard

Let $\sigma$ be arc-length measure on $S^1\subset \mathbb R^2$ and $\Theta$ denote rotation by an angle $\theta \in (0, \pi]$. Define a model bilinear generalized Radon transform, $$B_{\theta}(f,g)(x)=\int_{S^1} f(x-y)g(x-\Theta y)\,…

Classical Analysis and ODEs · Mathematics 2017-04-05 Allan Greenleaf , Alex Iosevich , Ben Krause , Allen Liu

The Radon transform is a bounded operator from L^p of Euclidean space R^d to L^q of the Grassmann manifold of all affine hyperplanes in R^d, for certain exponents. We identify all extremizers of the associated inequality for the endpoint…

Classical Analysis and ODEs · Mathematics 2011-06-06 Michael Christ

Polarization properties of strange baryons produced in pp reactions, p + p -> p + Lambda^0 + K^+ and p + p -> p + Sigma^0 + K^$, near thresholds of the final states (p Lambda^0 K^+) and (p Sigma^0 K^+) are analysed relative to polarizations…

Calculating opacities for a wide range of plasma conditions (i.e. temperature, density, element) requires detailed knowledge of the plasma configuration space and electronic structure. For plasmas composed of heavier elements, relativistic…

Plasma Physics · Physics 2023-05-02 Nathanael Gill , Christopher Fontes , Charles Starrett

An alternative method to invert the Radon transforms without the use of Courant-Hilbert's identities has been proposed and developed independently from the space dimension. For the universal representation of inverse Radon transform, we…

Classical Analysis and ODEs · Mathematics 2025-06-23 I. V. Anikin

This paper establishes $L^p$-improving estimates for a variety of Radon-like transforms which integrate functions over submanifolds of intermediate dimension. In each case, the results rely on a unique notion of curvature which relates to,…

Classical Analysis and ODEs · Mathematics 2016-09-13 Philip T. Gressman

We establish asymptotic bounds on the L^p norms of spectrally localized functions in the case of two-dimensional Dirichlet forms with coefficients of Lipschitz regularity. These bounds are new for the range p>6. A key step in the proof is…

Analysis of PDEs · Mathematics 2007-09-19 Herbert Koch , Hart F. Smith , Daniel Tataru

We obtain new $L_p$ estimates for subsolutions to fully nonlinear equations. Based on our $L_p$ estimates, we further study several topics such as the third and fourth order derivative estimates for concave fully nonlinear equations,…

Analysis of PDEs · Mathematics 2024-12-17 Hongjie Dong , Shuhei Kitano

We initiate the study of the $\ell^p(\mathbb{Z}^d)$-boundedness of the arithmetic spherical maximal function over sparse sequences. We state a folklore conjecture for lacunary sequences, a key example of Zienkiewicz and prove new bounds for…

Classical Analysis and ODEs · Mathematics 2016-09-15 Kevin Hughes

In this paper modified variants of the sparse Fourier transform algorithms from [14] are presented which improve on the approximation error bounds of the original algorithms. In addition, simple methods for extending the improved sparse…

Numerical Analysis · Mathematics 2010-10-04 M. A. Iwen

The cross sections for the reactions of the strange production p + p -> p + Lambda + K^+ and p + p -> p + Sigma^0 + K^+ near thresholds of the final states p Lambda K^+ and p Sigma^0 K^+ are calculated in the effective Lagrangian approach.…

High Energy Physics - Phenomenology · Physics 2009-10-31 A. Ya. Berdnikov , Ya. A. Berdnikov , A. N. Ivanov , V. F. Kosmach , M. D. Scadron , N. I. Troitskaya

In this paper we present the use of Sparse Radial Sampling Local Binary Patterns, a variant of Local Binary Patterns (LBP) for text-as-texture classification. By adapting and extending the standard LBP operator to the particularities of…

Computer Vision and Pattern Recognition · Computer Science 2015-04-24 Anguelos Nicolaou , Andrew D. Bagdanov , Marcus Liwicki , Dimosthenis Karatzas

We apply techniques from harmonic analysis to study the $L^p$ norms of Maass forms of varying level on a quaternion division algebra. Our first result gives a candidate for the local bound for the sup norm in terms of the level, which is…

Number Theory · Mathematics 2016-07-13 Simon Marshall
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