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We present a grid-based non-parametric approach to obtain a triaxial three-dimensional luminosity density from its surface brightness distribution. Triaxial deprojection is highly degenerate and our approach illustrates the resulting…

Astrophysics of Galaxies · Physics 2020-07-08 Stefano de Nicola , Roberto P. Saglia , Jens Thomas , Walter Dehnen , Ralf Bender

We consider the method of alternating projections for finding a point in the intersection of two closed sets, possibly nonconvex. Assuming only the standard transversality condition (or a weaker version thereof), we prove local linear…

Optimization and Control · Mathematics 2016-08-12 D. Drusvyatskiy , A. D. Ioffe , A. S. Lewis

We present a learnt system for multi-view stereopsis. In contrast to recent learning based methods for 3D reconstruction, we leverage the underlying 3D geometry of the problem through feature projection and unprojection along viewing rays.…

Computer Vision and Pattern Recognition · Computer Science 2017-08-18 Abhishek Kar , Christian Häne , Jitendra Malik

There exist efficient algorithms to project a point onto the intersection of a convex cone and an affine subspace. Those conic projections are in turn the work-horse of a range of algorithms in conic optimization, having a variety of…

Optimization and Control · Mathematics 2011-03-09 Didier Henrion , Jérôme Malick

In this study, we define a brief description of the hyperbolic and elliptic rotational surfaces using a curve and matrices in 4-dimensional semi Euclidean space. That is, we provide different types of rotational matrices, which are the…

Differential Geometry · Mathematics 2023-06-13 Fatma Almaz , Mihriban Alyamaç Külahcı

Quadrilateral layouts on surfaces are valuable in texture mapping, and essential in generation of quadrilateral meshes and in fitting splines. Previous work has characterized such layouts as a special metric on a surface or as a meromorphic…

Computational Geometry · Computer Science 2020-12-18 Kendrick M. Shepherd , René R. Hiemstra , Thomas J. R. Hughes

Surveillance and surveying are two important applications of empirical research. A major part of terrain modelling is supported by photographic surveys which are used for capturing expansive natural surfaces using a wide range of sensors --…

Image and Video Processing · Electrical Eng. & Systems 2023-05-16 Maniratnam Mandal , Venkatesh K. Subramanian

We give new estimates for the extrinsic radius of compact hypersurfaces of the Euclidean space and the open hemisphere in terms of high order mean curvatures. Then we prove pinching results corresponding to theses estimates. We show that…

Differential Geometry · Mathematics 2007-10-30 Julien Roth

We show that the four best-known substitutions used to integrate secant rely on different rational parametrizations of conic sections, coming from stereographic projections. We also investigate other possible explanations for the four…

History and Overview · Mathematics 2022-04-26 George Jennings , David Ni , Wai Yan Pong , Serban Raianu

We study effective versions of unlikely intersections of images of torsion points of elliptic curves on the projective line.

Algebraic Geometry · Mathematics 2017-06-07 Fedor Bogomolov , Hang Fu , Yuri Tschinkel

First we introduce a generalization of symmetric spaces to parabolic geometries. We provide construction of such parabolic geometries starting with classical symmetric spaces and we show that all regular parabolic geometries with smooth…

Differential Geometry · Mathematics 2012-07-30 Jan Gregorovič

We present a survey of some results and questions related to the notion of scalar curvature in the setting of symplectic supermanifolds.

Differential Geometry · Mathematics 2018-05-11 Rosalía Hernández-Amador , Juan Monterde , José A Vallejo

We propose Differentiable Stereopsis, a multi-view stereo approach that reconstructs shape and texture from few input views and noisy cameras. We pair traditional stereopsis and modern differentiable rendering to build an end-to-end model…

Computer Vision and Pattern Recognition · Computer Science 2022-09-27 Shubham Goel , Georgia Gkioxari , Jitendra Malik

We study the geometry of surfaces in $\mathbb{R}^{4}$ with corank $1$ singularities. For such surfaces the singularities are isolated and at each point we define the curvature parabola in the normal space. This curve codifies all the second…

Differential Geometry · Mathematics 2019-09-17 Pedro Benedini Riul , Raúl Oset Sinha , Maria Aparecida Soares Ruas

We give the classification of constant mean curvature rotational surfaces of elliptic, hyperbolic, and parabolic type in the four-dimensional pseudo-Euclidean space with neutral metric.

Differential Geometry · Mathematics 2016-03-03 Yana Aleksieva , Velichka Milousheva

This paper is concerned with the problem of prescribing Gaussian curvature and geodesic curvature in a compact surface with boundary with conical singularities and corners. Solutions are obtained using a new variational formulation,…

Analysis of PDEs · Mathematics 2025-08-18 Luca Battaglia , Francisco Javier Reyes-Sanchez

In the present paper we study the problem of constructing a family of surfaces (surface pencils) from a given curve in 4-dimensional Euclidean space $\mathbb{E}^{4}$. We have shown that generalized rotation surfaces in $\mathbb{E}^{4}$ are…

Differential Geometry · Mathematics 2015-05-18 Betül Bulca , Kadri Arslan

We prove the existence of a hyperbolic surface spread over the sphere for which the projection map has all its singular values on the extended real line, and such that the preimage of the extended real line under the projection map is…

Complex Variables · Mathematics 2014-04-04 Lukas Geyer , Sergei Merenkov

Given a triangulation of a closed surface, we consider a cross ratio system that assigns a complex number to every edge satisfying certain polynomial equations per vertex. Every cross ratio system induces a complex projective structure…

Geometric Topology · Mathematics 2021-05-05 Wai Yeung Lam

This paper considers a conceptual version of a convex optimization algorithm whic is based on replacing a convex optimization problem with the root-finding problem for the approximate sub-differential mapping which is solved by repeated…

Optimization and Control · Mathematics 2018-06-18 Evgeni Nurminski
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