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We consider the locus of irreducible nonsingular rational curves of degree d Pn, n>2, meeting a generic collection of linear subspaces. When this locus is 0 (resp 1)- dimensional, we compute (recursively) its degree (resp. geometric genus).…

alg-geom · Mathematics 2007-05-23 Z. Ran

Let $X$ be a real algebraic convex 3-manifold whose real part is equipped with a $Pin^-$ structure. We show that every irreducible real rational curve with non-empty real part has a canonical spinor state belonging to $\{\pm 1\}$. The main…

Algebraic Geometry · Mathematics 2007-05-23 Jean-Yves Welschinger

We show that we can obtain a reducible spherical curve from any non-trivial spherical curve by four or less inverse-half-twisted splices, i.e., the reductivity, which represents how reduced a spherical curve is, is four or less. We also…

Geometric Topology · Mathematics 2014-01-17 Ayaka Shimizu

The purpose of this note is to prove that there is an algebraic stack U parameterizing all curves. The curves that appear in the algebraic stack U are allowed to be arbitrarily singular, non-reduced, disconnected, and reducible. We also…

Algebraic Geometry · Mathematics 2010-11-30 Jack Hall

We study the existence of components with the expected number of moduli of the Hilbert scheme of integral nodal curves $C \subset \mathbb {P}^r$ with prescribed degree, arithmetic genus and number of singular points.

Algebraic Geometry · Mathematics 2013-04-23 Edoardo Ballico

In mathematics curves are typically defined as the images of continuous real functions (parametrizations) defined on a closed interval. They can also be defined as connected one-dimensional compact subsets of points. For simple curves of…

Computational Geometry · Computer Science 2015-07-01 Xizhong Zheng , Robert Rettinger

The boundary of the convex hull of a compact algebraic curve in real 3-space defines a real algebraic surface. For general curves, that boundary surface is reducible, consisting of tritangent planes and a scroll of stationary bisecants. We…

Algebraic Geometry · Mathematics 2011-01-19 Kristian Ranestad , Bernd Sturmfels

The cut polytope ${\rm CUT}(n)$ is the convex hull of the cut vectors in a complete graph with vertex set $\{1,\ldots,n\}$. It is well known in the area of combinatorial optimization and recently has also been studied in a direct relation…

Discrete Mathematics · Computer Science 2018-12-11 Nevena Maric

Consider the family S of irreducible plane curves of degree n with d nodes and k cusps as singularities. Let W be an irreducible component of S. We consider the natural rational map from W to the moduli space of curves of genus…

Algebraic Geometry · Mathematics 2007-05-23 Concettina Galati

It is shown that a simple closed curve in $\mathbb C^n$ that is a uniform limit of rectifiable simple closed curves each of which has nontrivial polynomial hull has itself nontrivial polynomial hull. In case the limit curve is rectifiable,…

Complex Variables · Mathematics 2021-05-21 Alexander J. Izzo , Edgar Lee Stout

Let $K$ be a number field, and $g \geq 2$ a positive integer. We define $c_K(g)$ as the smallest integer $n$ such that there exist infinitely many $\overline{K}$-isomorphism classes of genus $g$ hyperelliptic curves $C/K$ with all…

Number Theory · Mathematics 2022-01-21 Robin Visser

In this paper, we analyze the planar cubic Alternative curve to determine the conditions for convex, loops, cusps and inflection points. Thus cubic curve is represented by linear combination of three control points and basis function that…

Graphics · Computer Science 2013-05-01 Azhar Ahmad , R. Gobithasan , Jamaluddin Md. Ali

We ask whether every polynomial function that is non-negative on a real algebraic curve can be expressed as a sum of squares in the coordinate ring. Scheiderer has classified all irreducible curves for which this is the case. For reducible…

Algebraic Geometry · Mathematics 2009-03-09 Daniel Plaumann

There are thirteen types of singular points for irreducible real quartic curves and seventeen types of singular points for reducible real quartic curves. This classification is originally due to D.A. Gudkov. There are nine types of singular…

Algebraic Geometry · Mathematics 2007-07-03 David A. Weinberg , Nicholas J. Willis

We study connections between self-inversive and self-reciprocal polynomials, reduction theory of binary forms, minimal models of curves, and formally self-dual codes. We prove that if $\mathcal X$ is a superelliptic curve defined over…

Complex Variables · Mathematics 2019-05-30 David Joyner , Tony Shaska

We initiate the study of a class of real plane algebraic curves which we call expressive. These are the curves whose defining polynomial has the smallest number of critical points allowed by the topology of the set of real points of a…

Algebraic Geometry · Mathematics 2023-08-29 Sergey Fomin , Eugenii Shustin

We classify the three-dimensional representations of the modular group that are reducible but indecomposable, and their associated spaces of holomorphic vector-valued modular forms. We then demonstrate how such representations may be…

Number Theory · Mathematics 2017-10-17 Luca Candelori , Tucker Hartland , Christopher Marks , Diego Yepez

Generalizing a classical lemma of Castelnuovo, we characterize rational normal curves (resp. linearly normal elliptic curves) as curves $C\subset \PP^n$ such that the number of linearly independent hypersurfaces $Z\supset C$ of given…

alg-geom · Mathematics 2008-02-03 S. L'vovsky

Let $\mathcal C$ be a real plane algebraic curve defined by the resultant of two polynomials (resp. by the discriminant of a polynomial). Geometrically such a curve is the projection of the intersection of the surfaces $P(x,y,z)=Q(x,y,z)=0$…

Computational Geometry · Computer Science 2015-05-26 Rémi Imbach , Guillaume Moroz , Marc Pouget

We consider general integrable curve nets in Euclidean space as a particular integrable geometry invariant with respect to rigid motions and net-preserving reparameterisations. For the purpose of their description, we first give an overview…

Differential Geometry · Mathematics 2025-04-29 Michal Marvan