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In this paper, close surfaces are considered in 3-dimensional harmonic conformally flat space in point of the variation. It is shown that if the conformal vector field be tangent to surface and the sign of the mean curvature does not change…

Differential Geometry · Mathematics 2021-08-16 Najma mosadegh , Esmaiel Abedi

In this Letter we suggest a method of convex rigid frames in the studies of the multipartite quNit pure-states. We illustrate what are the convex rigid frames and what is the method of convex rigid frames. As the applications we use this…

Quantum Physics · Physics 2009-11-10 Zai-Zhe Zhong

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

This paper aims to develop the mathematical representation of a surface generated by elliptical arcs joining the sides of a regular polygon to a point lying vertically upward on the central axis of the polygon. The volume of the…

History and Overview · Mathematics 2020-09-02 Shahid Saeed Siddiqi , Abdul Rauf Nizami

We review some basic results of convex analysis and geometry in $\mathbb{R}^n$ in the context of formulating a differential equation to track the distance between an observer flying outside a convex set $K$ and $K$ itself.

Dynamical Systems · Mathematics 2019-06-19 J. J. P. Veerman

In 3-d the average projected area of a convex solid is 1/4 the surface area, as Cauchy showed in the 19th century. In general, the ratio in n dimensions may be obtained from Cauchy's surface area formula, which is in turn a special case of…

Differential Geometry · Mathematics 2012-11-13 Zachary Slepian

Pick $d+1$ points uniformly at random on the unit sphere in $\mathbb R^d$. What is the expected value of the angle sum of the simplex spanned by these points? Choose $n$ points uniformly at random in the $d$-dimensional ball. What is the…

Probability · Mathematics 2020-03-04 Zakhar Kabluchko

This paper consists of four general parts: convex sets; convex functions; convex optimization; and the interior-point algorithm. I will start by introducing the definition of convex sets and give three common convex set examples which will…

Optimization and Control · Mathematics 2020-09-28 Haoqian Li

This paper introduces a natural definition for the volume of the unit ball in $n$-dimensional normed spaces $\mathbb{R}^n$. This definition preserves the Euclidean relation $P(B)/V(B)=n$ between the perimiter and the volume of the unit ball…

Metric Geometry · Mathematics 2026-05-05 Gershon Wolansky

Straight lines are common features in human made environments, which makes them a frequently explored feature for control applications. Many control schemes, like Visual Servoing, require the 3D parameters of the features to be estimated.…

Robotics · Computer Science 2019-03-22 André Mateus , Omar Tahri , Pedro Miraldo

The main objective of the present paper is to investigate a sufficient condition for which a rectifying curve on a smooth surface remains invariant under isometry of surfaces, and also it is shown that under such an isometry the component…

General Mathematics · Mathematics 2018-08-13 Absos Ali Shaikh , Pinaki Ranjan Ghosh

We study infinitesimal conformal deformations of a triangulated surface in Euclidean space and investigate the change in its extrinsic geometry. A deformation of vertices is conformal if it preserves length cross-ratios. On one hand,…

Metric Geometry · Mathematics 2018-04-19 Wai Yeung Lam , Ulrich Pinkall

An analogue of the total variation prior for the normal vector field along the boundary of piecewise flat shapes in 3D is introduced. A major class of examples are triangulated surfaces as they occur for instance in finite element…

Numerical Analysis · Mathematics 2020-06-24 Ronny Bergmann , Marc Herrmann , Roland Herzog , Stephan Schmidt , José Vidal Núñez

Given a compact subset $F$ of $\mathbb{R}^2$, the visible part $V_\theta F$ of $F$ from direction $\theta$ is the set of $x$ in $F$ such that the half-line from $x$ in direction $\theta$ intersects $F$ only at $x$. It is suggested that if…

Metric Geometry · Mathematics 2013-07-26 Kenneth J. Falconer , Jonathan M. Fraser

Our goal is to identify the type and number of static equilibrium points of solids arising from fine, equidistant $n$-discretrizations of smooth, convex surfaces. We assume uniform gravity and a frictionless, horizontal, planar support. We…

Differential Geometry · Mathematics 2011-12-02 Gabor Domokos , Zsolt Langi , Timea Szabo

This paper studies the convex hull of $d$-dimensional samples i.i.d. generated from spherically symmetric distributions. Specifically, we derive a complete integration formula for the expected facet number of the convex hull. This formula…

Probability · Mathematics 2024-02-16 Feng Zhao , Xinyi Tong , Shao-Lun Huang

The manuscript provides formulas for the volume of a body defined by the intersection of a solid cone and a solid sphere as a function of the sphere radius, of the distance between cone apex and sphere center, and of the cone aperture…

Classical Analysis and ODEs · Mathematics 2023-08-15 Richard J. Mathar

A number of results for C$^2$-smooth surfaces of constant width in Euclidean 3-space ${\mathbb{E}}^3$ are obtained. In particular, an integral inequality for constant width surfaces is established. This is used to prove that the ratio of…

Differential Geometry · Mathematics 2021-11-15 Brendan Guilfoyle , Wilhelm Klingenberg

At any point of a surface in the four-dimensional Euclidean space we consider the geometric configuration consisting of two figures: the tangent indicatrix, which is a conic in the tangent plane, and the normal curvature ellipse. We show…

Differential Geometry · Mathematics 2009-05-28 Georgi Ganchev , Velichka Milousheva

In this study, after given the definition of soft sets and their basic operations we define convex soft sets which is an important concept for operation research, optimization and related problems. Then, we define concave soft sets and give…

General Mathematics · Mathematics 2013-07-19 Irfan Deli