Ghezzi: Tangency points in almost-Riemannian geometry
An almost-Riemannian structure on a surface is a generalized Riemannian structure whose local orthonormal frames are given by Lie bracket generating pairs of vector fields that can become collinear. Generically, there are three types of points: Riemannian points where the two vector fields are linearly independent, Grushin points where the two vector fields are collinear but their Lie bracket is not, and tangency points where the two vector fields and their Lie bracket are collinear and the missing direction is obtained with one more bracket. In this talk we study local properties of generic almost-Riemannian surfaces near tangency points. Moreover, we consider the Carnot–Caratheodory distance associated with an almost-Riemannian structure and study the problem of Lipschitz equivalence between two such distances on the same compact oriented surface. We characterize the Lipschitz equivalence class of an almost-Riemannian distance in terms of a labelled graph associated with it. http://cvgmt.sns.it/seminar/303/
When
Wed Nov 28, 2012 4pm – 5pm Coordinated Universal Time
Where
Sala Seminari, Department of Mathematics, Pisa University (map)
