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It is shown that time-harmonic motions of spherical and toroidal surfaces can be deformed non-locally without loosing the existence of infinitely many constants of the motion.

High Energy Physics - Theory · Physics 2007-05-23 Jens Hoppe

We establish coupled fixed point theorems for contraction involving rational expressions in partially ordered metric spaces.

General Topology · Mathematics 2010-05-19 Bessem Samet , Habib Yazidi

In this paper we prove two theorems. The first one is a structure result that describes the extrinsic geometry of an embedded surface with constant mean curvature (possibly zero) in a homogeneously regular Riemannian three-manifold, in any…

Differential Geometry · Mathematics 2014-01-10 William H. Meeks , Joaquín Pérez , Antonio Ros

In this paper we prove Morse index theorems for a big class of constrained variational problems on graphs. Such theorems are useful in various physical and geometric applications. Our formulas compute the difference of Morse indices of two…

Optimization and Control · Mathematics 2023-04-19 Andrei Agrachev , Stefano Baranzini , Ivan Beschastnyi

This paper demonstrates a practical method that can correct spatial varying blur from a set of images of the same object. The algorithm jointly estimates the object and local point spread functions~(PSF). The method prioritizes sections…

Image and Video Processing · Electrical Eng. & Systems 2020-11-04 Wouter van de Ketterij , Oleg Soloviev , Michel Verhaegen

CSP sparsification, introduced by Kogan and Krauthgamer (ITCS 2015), considers the following question: how much can an instance of a constraint satisfaction problem be sparsified (by retaining a reweighted subset of the constraints) while…

Data Structures and Algorithms · Computer Science 2024-11-07 Sanjeev Khanna , Aaron L. Putterman , Madhu Sudan

Following ideas from a preprint of the second author, see [2], we investigate relations of dynamical Teichmuller spaces with dynamical objects. We also establish some connections with the theory of deformations of inverse limits and…

Dynamical Systems · Mathematics 2009-12-01 Carlos Cabrera , Peter Makienko

The subject of simulating internal organs is a valuable and important topic of research to multiple fields from medical analysis to education and training. This paper presents a solution that utilizes a graphical technique in combination…

Graphics · Computer Science 2024-01-23 Benjamnin Kenwright , Kanida Sinmai

The concept of rigid reference frame and of constricted spatial metric, given in the previous work [\emph{Class. Quantum Grav.} {\bf 21}, 3067,(2004)] are here applied to some specific space-times: In particular, the rigid rotating disc…

General Relativity and Quantum Cosmology · Physics 2008-11-26 D. Soler

The two-particle models in de Sitter space-time with time-asymmetric retarded-advanced interactions are constructed. Particular cases of the field-type electromagnetic and scalar interactions are considered. The manifestly covariant…

General Relativity and Quantum Cosmology · Physics 2026-02-18 Askold Duviryak

We consider the task of learning to extract motion from videos. To this end, we show that the detection of spatial transformations can be viewed as the detection of synchrony between the image sequence and a sequence of features undergoing…

Computer Vision and Pattern Recognition · Computer Science 2014-02-11 Kishore Reddy Konda , Roland Memisevic , Vincent Michalski

We introduce a simple representation for isotropic spherical random fields and we discuss how it allows to discuss different notions of sparsity under isotropy. We also show how a suitable construction of sparse fields can mimic well the…

Probability · Mathematics 2026-01-30 Giacomo Greco , Domenico Marinucci

Discrete sampling theorem is formulated that refers to discrete signals specified by a finite number of their samples and band-limited in a domain of a certain orthogonal transform. Conditions of the recoverability of such signals from…

Optics · Physics 2009-02-24 L. Yaroslavsky

Sparse representation of astronomical images is discussed. It is shown that a significant gain in sparsity is achieved when particular mixed dictionaries are used for approximating these types of images with greedy selection strategies.…

Mathematical Physics · Physics 2015-06-11 Laura Rebollo-Neira , James Bowley

This is a short note to announce the availability of some movies that may be useful in classroom discussions on the photographic appearance of objects moving at relativistic speeds. The images are based on special relativity with no account…

Physics Education · Physics 2007-05-23 Leo Brewin

Learned data models based on sparsity are widely used in signal processing and imaging applications. A variety of methods for learning synthesis dictionaries, sparsifying transforms, etc., have been proposed in recent years, often imposing…

Machine Learning · Computer Science 2018-10-22 Saiprasad Ravishankar , Brendt Wohlberg

We examine in this paper the problem of image registration from the new perspective where images are given by sparse approximations in parametric dictionaries of geometric functions. We propose a registration algorithm that looks for an…

Computer Vision and Pattern Recognition · Computer Science 2013-12-31 Alhussein Fawzi , Pascal Frossard

In this exploration paper, we design algorithms for deforming and contracting a simply connected discrete closed manifold to a discrete sphere. Such a contraction is a kind of shrinking or reducing process. In our algorithms, we need to…

General Topology · Mathematics 2015-07-28 Li Chen

Recent work of [Dasgupta-Kumar-Sarlos, STOC 2010] gave a sparse Johnson-Lindenstrauss transform and left as a main open question whether their construction could be efficiently derandomized. We answer their question affirmatively by giving…

Data Structures and Algorithms · Computer Science 2010-12-08 Daniel M. Kane , Jelani Nelson

We provide here a proof theoretic account of constraint programming that attempts to capture the essential ingredients of this programming style. We exemplify it by presenting proof rules for linear constraints over interval domains, and…

Artificial Intelligence · Computer Science 2007-05-23 Krzysztof R. Apt