Cyclic quadrangles from squares.
Dynamical Systems for Rational Normal Curves.
Elementary Albeian p-Extensions of Algebraic Function Fields.
Elliptic curves with j-invariant equals 0 or 1728 over a finite prime field.
Let p be a prime number, p ≠ 2,3 and Fp the finite field with p elements. An elliptic curve E over Fp is a projective nonsingular curve of genus 1 defined over Fp. Each one of these curves has an isomorphic model given by an (Weierstrass) equation E: y2 = x3 + Ax + B, A,B ∈ Fp with D = 4A3 + 27B2 ≠ 0. The j-invariant of E is defined by j(E) = 1728·4A3/D.The aim of this note is to establish some results concerning the cardinality of the group of points on elliptic curves over Fp with j-invariants...
Erratum to “Fundamental groups of some special quadric arrangements”.
Experimental study of the rank of families of elliptic curves over . (Étude expérimentale du rang de familles de courbes elliptiques sur .)
Fundamental groups of some special quadric arrangements.
Continuing our work on the fundamental groups of conic-line arrangements (Amram et al., 2003), we obtain presentations of fundamental groups of the complements of three families of quadric arrangements in P2. The first arrangement is a union of n conics, which are tangent to each other at two common points. The second arrangement is composed of n quadrics which are tangent to each other at one common point. The third arrangement is composed of n quadrics, n-1 of them are tangent to the n-th one...
Gaudin's model and the generating function of the Wroński map
We consider the Gaudin model associated to a point z ∈ ℂⁿ with pairwise distinct coordinates and to the subspace of singular vectors of a given weight in the tensor product of irreducible finite-dimensional sl₂-representations, [G]. The Bethe equations of this model provide the critical point system of a remarkable rational symmetric function. Any critical orbit determines a common eigenvector of the Gaudin hamiltonians called a Bethe vector. In [ReV], it was shown that for generic...
Geometrické modelování – od historie k současnosti a budoucnosti
Implementing 2-descent for Jacobians of hyperelliptic curves
Linear systems over ℙ¹×ℙ¹ with base points of multiplicity bounded by three
We propose a combinatorial method of proving non-specialty of a linear system of curves with multiple points in general position. As an application, we obtain a classification of special linear systems on ℙ¹×ℙ¹ with multiplicities not exceeding 3.
Meandering of trajectories of polynomial vector fields in the affine n-space.
We give an explicit upper bound for the number of isolated intersections between an integral curve of a polynomial vector field in Rn and an affine hyperplane.The problem turns out to be closely related to finding an explicit upper bound for the length of ascending chains of polynomial ideals spanned by consecutive derivatives.This exposition constitutes an extended abstract of a forthcoming paper: only the basic steps are outlined here, with all technical details being either completely omitted...
Myrberg's numerical uniformization of hyperelliptic curves.
On the complexity of parametrizing curves.
On the computation of Weierstrass gap sequences.
Optimal degree construction of real algebraic plane nodal curves with prescribed topology. I. The orientable case.
We study a constructive method to find an algebraic curve in the real projective plane with a (possibly singular) topological type given in advance. Our method works if the topological model T to be realized has only double singularities and gives an algebraic curve of degree 2N+2K, where N and K are the numbers of double points and connected components of T. This degree is optimal in the sense that for any choice of the numbers N and K there exist models which cannot be realized algebraically with...
Puiseux Expansion of a Cuspidal Singularity
We present an effective and elementary method of determining the topological type of a cuspidal plane curve singularity with given local parametrization.
Quasi-homogeneous linear systems on ℙ² with base points of multiplicity 7, 8, 9, 10
We prove that the Segre-Gimigliano-Harbourne-Hirschowitz conjecture holds for quasi-homogeneous linear systems on ℙ² for m = 7, 8, 9, 10, i.e. systems of curves of a given degree passing through points in general position with multiplicities at least m,...,m,m₀, where m = 7, 8, 9, 10, m₀ is arbitrary.
Rational Bézier curves with infinitely many integral points
In this paper we consider rational Bézier curves with control points having rational coordinates and rational weights, and we give necessary and sufficient conditions for such a curve to have infinitely many points with integer coefficients. Furthermore, we give algorithms for the construction of these curves and the computation of theirs points with integer coefficients.
Recovering an algebraic curve using its projections from different points. Applications to static and dynamic computational vision
We study some geometric configurations related to projections of an irreducible algebraic curve embedded in onto embedded projective planes. These configurations are motivated by applications to static and dynamic computational vision. More precisely, we study how an irreducible closed algebraic curve embedded in , of degree and genus , can be recovered using its projections from points onto embedded projective planes. The embeddings are unknown. The only input is the defining equation of...