19–21 nov. 2025
IHES
Fuseau horaire Europe/Paris

Minimal Polynomial Parameterization of Rational Knots

21 nov. 2025, 14:50
50m
Centre de conférences Marilyn et James Simons (IHES)

Centre de conférences Marilyn et James Simons

IHES

Le Bois-Marie 35, route de Chartres 91440 Bures-sur-Yvette

Orateur

Pierre-Vincent Koseleff (IMJ-PRG)

Description

A polynomial parameterization of a knot $K$ in $S^3$ is a polynomial map $\gamma : \mathbf{R} \to \mathbf{R}^3$ whose closure of the image in $S^3$ is isotopic to $K$. Every knot admits a polynomial parametrisation, and we are interested in determining the lexicographic degree of a knot $K$, i.e. the minimal degree for the lexicographic order of a polynomial parametrisation of $K$.
We give the lexicographic degree of all two-bridge knots with 12 or fewer crossings. First, we estimate the total degree of a lexicographic parametrisation of such a knot. This allows us to transform this problem into a study of real algebraic trigonal plane curves, and in particular to use the braid theoretical method developed by Orevkov.
Joint work with E. Brugallé an D. Pecker

Documents de présentation