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This survey paper concerns elliptic surfaces with section. We give a detailed overview of the theory including many examples. Emphasis is placed on rational elliptic surfaces and elliptic K3 surfaces. To this end, we particularly review the…

Algebraic Geometry · Mathematics 2010-07-12 Matthias Schuett , Tetsuji Shioda

We prove that the isometric embedding of any metric of differentiability class C1 in E3 exists. We use simplified notation for the given metric, namely geodesic parameters, and level parameters for the embedded surface in E3. Central to our…

Differential Geometry · Mathematics 2022-10-07 Edgar Kann

We present a general algorithm for finding the overlap area between two ellipses. The algorithm is based on finding a segment area (the area between an ellipse and a secant line) given two points on the ellipse. The Gauss-Green formula is…

Computational Physics · Physics 2011-06-21 Gary B. Hughes , Mohcine Chraibi

The solution of the geodesic problem for an oblate ellipsoid is developed in terms of series. Tables are provided to simplify the computation. [This is an English translation of F. W. Bessel, Astronomische Nachrichten 4(86), 241-254 (1825).…

Computational Physics · Physics 2012-03-30 F. W. Bessel , Charles F. F. Karney , Rodney E. Deakin

In this paper we consider Yamabe type problem for higher order curvatures on manifolds with totally geodesic boundaries. We prove local gradient and second derivative estimates for solutions to the fully nonlinear elliptic equations…

Differential Geometry · Mathematics 2011-12-14 Yan He , Weimin Sheng

The curvature estimates of quotient curvature equation do not always exist even for convex setting \cite{GRW}. Thus it is natural question to find other type of elliptic equations possessing curvature estimates. In this paper, we discuss…

Analysis of PDEs · Mathematics 2017-05-30 Chunhe Li , Changyu Ren , Zhizhang Wang

In this paper, we propose using the scattering surface area rather than the scattering cross section to characterize the scattering behavior of ellipsoidal rigid bodies. We examined the scattering behavior of ellipsoidal rigid bodies,…

Optics · Physics 2025-04-21 Youning Li

This article investigates, by probabilistic methods, various geometric questions on B_p^n, the unit ball of \ell_p^n. We propose realizations in terms of independent random variables of several distributions on B_p^n, including the…

Probability · Mathematics 2007-05-23 Franck Barthe , Olivier Guedon , Shahar Mendelson , Assaf Naor

An asymptotic formula is proved for the expected $T$-functional of the convex hull of independent and identically distributed random points sampled from the Euclidean unit sphere in $\mathbb{R}^n$ according to an arbitrary positive…

Probability · Mathematics 2023-08-02 Steven Hoehner , Ben Li , Michael Roysdon , Christoph Thäle

This paper considers some fundamental questions concerning marginally trapped surfaces, or apparent horizons, in Cauchy data sets for the Einstein equation. An area estimate for outermost marginally trapped surfaces is proved. The proof…

General Relativity and Quantum Cosmology · Physics 2009-08-05 Lars Andersson , Jan Metzger

We test the methods developed in previous papers for inferring the intrinsic shapes of elliptical galaxies, using simulated objects from N-body experiments. The shapes of individual objects are correctly reproduced to within the statistical…

Astrophysics · Physics 2009-10-31 T. S. Statler

Embedding diagrams prove to be quite useful when learning general relativity as they offer a way of visualizing spacetime curvature through warped two dimensional (2D) surfaces. In this manuscript we present a different 2D construct that…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Chad A. Middleton

We overview the volume calculations for polyhedra in Euclidean, spherical and hyperbolic spaces. We prove the Sforza formula for the volume of an arbitrary tetrahedron in $H^3$ and $S^3$. We also present some results, which provide a…

Metric Geometry · Mathematics 2013-02-28 Nikolay Abrosimov , Alexander Mednykh

If E is any ellipse inscribed in a convex quadrilateral, D, then we prove that Area(E)/Area(D) is less than or equal to pi/4, and equality holds if and only if D is a parallelogram and E is tangent to the sides of D at the midpoints. This…

Classical Analysis and ODEs · Mathematics 2011-07-29 Alan Horwitz

We prove a topological rigidity theorem for closed hypersurfaces of the Euclidean sphere and of an elliptic space form. It asserts that, under a lower bound hypothesis on the absolute value of the principal curvatures, the hypersurface is…

Differential Geometry · Mathematics 2018-09-28 Eduardo Longa , Jaime Ripoll

We obtain $C^2$ a priori estimates for solutions of the nonlinear second-order elliptic equation related to the geometric problem of finding a strictly locally convex hypersurface with prescribed curvature and boundary in a space form.…

Differential Geometry · Mathematics 2019-02-22 Zhenan Sui

In this paper we obtain density estimates for compact surfaces immersed in R^n with total boundary curvature less than 4pi and with sufficiently small L^p norm of the mean curvature, p>2. Our results generalize the main results in [2]. We…

Differential Geometry · Mathematics 2011-05-11 Theodora Bourni , Giuseppe Tinaglia

This paper introduces new definitions of common geodetic measures on a planetary surface (namely surface area, path length, and mean value or other statistical parameters of a surface function) that are not based on a datum such as a…

Earth and Planetary Astrophysics · Physics 2022-12-27 Kai Xu

A very general surface of degree at least four in projective space of dimension three contains no curves other than intersections with surfaces. We find a formula for the degree of the locus of surfaces of degree at least five which contain…

Algebraic Geometry · Mathematics 2014-07-09 Fernando Cukierman , Angelo Lopez , Israel Vainsencher

We present a survey article about the geometry of convex bodies on the $d$-dimensional sphere $S^d$. We concentrate on the results based on the notion of the width of a convex body $C \subset S^d$ determined by a supporting hemisphere of…

Metric Geometry · Mathematics 2021-06-30 Marek Lassak