Séminaire Géométrie et groupes discrets

Rational Approximations to Linear Subspaces

par Nicolas de Saxcé (CNRS & Université Paris-Nord)

Europe/Paris
Amphithéâtre Léon Motchane (IHES)

Amphithéâtre Léon Motchane

IHES

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

Dirichlet's theorem in Diophantine approximation implies that for any real x, there exists a rational p/q arbitrarily close to x such that |x-p/q| < 1/q2. In addition, the exponent 2 that appears in this inequality is optimal, as seen for example by taking $x=\sqrt2$. In 1967, Wolfgang Schmidt suggested a similar problem, where x is a real subspace of Rd of dimension ℓ, which one seeks to approximate by a rational subspace v. Our goal will be to obtain the optimal value of the exponent in the analogue of Dirichlet's theorem within this framework. The proof is based on a study of diagonal orbits in the space of lattices in Rd.

Organisé par

Fanny Kassel

Contact