Parametric and Non-Parametric Minima.
Planar vector field versions of Carathéodory's and Loewner's conjectures.
Let r = 3, 4, ... , ∞, ω. The Cr-Carathéodory's Conjecture states that every Cr convex embedding of a 2-sphere into R3 must have at least two umbilics. The Cr-Loewner's conjecture (stronger than the one of Carathéodory) states that there are no umbilics of index bigger than one. We show that these two conjectures are equivalent to others about planar vector fields. For instance, if r ≠ ω, Cr-Carathéodory's Conjecture is equivalent to the following one:Let ρ > 0 and β: U ⊂ R2 → R, be of class...
Prolongement des champs de vecteurs à des variétés de points proches