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We demonstrate a method for exact determination of the quadratic curve of minimal energy and minimal curvature variation through three non-colinear points in the plane, including methods to determine the tangent vector and curvature at any…

数值分析 · 数学 2010-10-25 Steven Benoit

We restate the semistable reduction theorem from geometric invariant theory in the context of spaces of morphisms on $\mathbb{P}^{n}$. For every complete curve $C$ downstairs, we get a $\mathbb{P}^{n}$-bundle on an abstract curve $D$…

代数几何 · 数学 2011-06-10 Alon Levy

Reconstructing a finite set of curves from an unordered set of sample points is a well studied topic. There has been less effort that considers how much better the reconstruction can be if tangential information is given as well. We show…

计算几何 · 计算机科学 2009-03-11 Leslie Greengard , Chris Stucchio

We give optimal lower bounds for the number of sextactic points on a simple closed curve in the real projective plane. Sextactic points are after inflection points the simplest projectively invariant singularities on such curves. Our method…

微分几何 · 数学 2007-05-23 Gudlaugur Thorbergsson , Masaaki Umehara

We propose a solution to the tenth of Professor Clark Kimberling's unsolved problems found on https://faculty.evansville.edu/ck6/integer/unsolved.html. We are required to find the parametric equations of a simple and closed curve $C$ on the…

综合数学 · 数学 2026-04-24 Thando Nkomozake

We recall two basic conjectures on the developables of convex projective curves, prove one of them and disprove the other in the firdt nontrivial case of curves in RP^3. Namely, we show that i) the tangent developable surface of any convex…

代数几何 · 数学 2007-05-23 V. Sedykh , B. Shapiro

In this paper, we study the curvature properties of random complex plane curves. We bound from below the probability that a uniform proportion of the area of a random complex degree $d$ plane curve has a curvature smaller than $-d/8$. Our…

代数几何 · 数学 2024-02-20 Michele Ancona , Damien Gayet

We prove a semistable reduction theorem for principal bundles on curves in almost arbitrary characteristics. For exceptional groups we need some small explicit restrictions on the characteristic.

代数几何 · 数学 2007-05-23 Jochen Heinloth

We prove a discrete analog of a certain four-vertex theorem for space curves. The smooth case goes back to the work of Beniamino Segre and states that a closed and smooth curve whose tangent indicatrix has no self-intersections admits at…

微分几何 · 数学 2025-01-22 Samuel Pacitti Gentil , Marcos Craizer

Denote by $S^2$ the two-dimensional sphere. A spherical convex body on $S^2$ which does not properly contain a spherical convex body of the same spherical thickness is called a reduced body. We give three characterizations of reducedness of…

度量几何 · 数学 2025-09-17 Marek Lassak

In characteristic $p>0$ and for $q$ a power of $p$, we compute the number of nonplanar rational curves of arbitrary degrees on a smooth Hermitian surface of degree $q+1$ under the assumption that the curves have a parametrization given by…

代数几何 · 数学 2020-03-31 Norifumi Ojiro

A Tangle is a smooth simple closed curve formed from arcs (or ``links'') of circles with fixed radius. Most previous study of Tangles has dealt with the case where these arcs are quarter-circles, but Tangles comprised of thirds and sixths…

组合数学 · 数学 2024-06-03 Rebecca M. Bowen , Sadie Pruitt , Douglas A. Torrance

The existence of translated curves for quasiperiodically forced maps is established, under very mild regularity hypotheses, for rotation numbers of constant type. Among the translated curves, the invariant curves are characterized as the…

动力系统 · 数学 2026-03-31 Amadeu Delshams , Rafael Ortega

Let $Z$ be a projective hypersurface such that its underlying reduced variety has only isolated singularities. In case its irreducible components have constant multiplicities, for instance if $\dim Z>1$, we show that the spectrum of its…

代数几何 · 数学 2025-08-08 Seung-Jo Jung , Morihiko Saito , Youngho Yoon

Curves in ${\mathbb R}^n$ for which the ratios between two consecutive curvatures are constant are characterized by the fact that their tangent indicatrix is a geodesic in a flat torus. For $n= 3,4$, spherical curves of this kind are also…

微分几何 · 数学 2007-05-23 J. Monterde

We give necessary and sufficient topological conditions for a simple closed curve on a real rational surface to be approximable by smooth rational curves. We also study approximation by smooth rational curves with given complex…

代数几何 · 数学 2025-05-26 János Kollár , Frédéric Mangolte

In this paper we show how, under surprisingly weak assumptions, one can split a planar curve into three arcs and rearrange them (matching tangent directions) to obtain a closed curve. We also generalize this construction to curves split…

微分几何 · 数学 2020-08-24 Leonardo Alese

We address the problem of the maximal finite number of real points of a real algebraic curve (of a given degree and, sometimes, genus) in the projective plane. We improve the known upper and lower bounds and construct close to optimal…

代数几何 · 数学 2019-09-13 Erwan Brugallé , Alex Degtyarev , Ilia Itenberg , Frédéric Mangolte

Let $X$ be a smooth irreducible projective curve of genus $g$ and gonality 4. We show that the canonical model of $X$ is contained in a uniquely defined surface, ruled by conics, whose geometry is deeply related to that of $X$. This surface…

代数几何 · 数学 2012-10-25 Michela Brundu , Gianni Sacchiero

We consider the problem of finding curves of minimum pointwise-maximum curvature, i.e., curves of minimax curvature, among planar curves of fixed length with prescribed endpoints and tangents at the endpoints. We reformulate the problem in…

最优化与控制 · 数学 2024-04-22 C. Yalçın Kaya , Lyle Noakes , Philip Schrader