Current CAD systems can represent curves and surfaces only in rational B-spline (NURBS) form ( .Farin, 1994; .Hoschek and Lasser, 1993). On the other hand, certain curves and surfaces that arise in practical applications such as offsets of rational curves or surfaces are in general not rational and therefore need to be approximated. This motivated .Farouki and Sakkalis (1990) to introduce the s...

The security of elliptic curve cryptosystem depends on the choice of an elliptic curve on which cryptographic operations are performed. Schoof’s algorithm is used to define a secure elliptic curve, as it can compute the number of rational points on a randomly selected elliptic curve defined over a finite field. By realizing efficient combination of several improvements, such as Atkin-Elkies’s m...

Given a parameterization of an algebraic rational curve in a projective space of arbitrary dimension, we introduce and study a new implicit representation of this curve which consists in the locus where the rank of a single matrix drops. Then, we illustrate the advantages of this representation by addressing several important problems of Computer Aided Geometric Design: The point-on-curve and i...

Approximating complex curves with simple parametric curves is widely used in CAGD, CG, and CNC. This paper presents an algorithm to compute a certified approximation to a given parametric space curve with cubic B-spline curves. By certified, we mean that the approximation can approximate the given curve to any given precision and preserve the geometric features of the given curve such as the to...

A polynomial relation f(x, y) = 0 in two variables defines a curve C. If the coefficients of the polynomial are rational numbers then one can ask for solutions of the equation f(x, y) = 0 with x, y ∈ Q, in other words for rational points on the curve. If we consider a non-singular projective model C of the curve then over C it is classified by its genus. Mordell conjectured, and in 1983 Falting...

A moving line Lðx; y; tÞ 1⁄4 0 is a family of lines with one parameter t in a plane. A moving line Lðx; y; tÞ 1⁄4 0 is said to follow a rational curve PðtÞ if the point Pðt0Þ is on the line Lðx; y; t0Þ 1⁄4 0 for any parameter value t0. A l-basis of a rational curve PðtÞ is a pair of lowest degree moving lines that constitute a basis of the module formed by all the moving lines following PðtÞ, w...