Date: Oct 11, 2011, time: 16:10
Place: Centro De Giorgi, Scuola Normale Superiore
Abstract. Carnot-Carathéodory spaces are a wide generalization of sub-Riemannian
manifolds which model nonholonomic processes and naturally arise in many applications. We consider the case of arbitrary weighted filtration of the tangent bundle (it generalizes the sub-Riemannian framework of a bracket-generating distribution) and study the local geometry of such spaces in a neighborhood of nonregular points (where dimensions of the subbundles generating the filtration may vary from point to point). In particular, we prove analogs of such classical results of sub-Riemannian geometry as Local approximation theorem and Tangent cone theorem. Quasimetrics are needed since, in the considered situation, the intrinsic Carnot-Carathéodory metric might not exist. The motivation of this research stems from nonlinear control theory and subelliptic equations.