Communications in Analysis and Geometry
Volume 29 (2021)
Model spaces in sub-Riemannian geometry
Pages: 77 – 113
We consider sub-Riemannian spaces admitting an isometry group that is maximal in the sense that any linear isometry between the horizontal tangent spaces is realized by a global isometry. We will show that these spaces have a canonical choice of partial connection on their horizontal bundle, which is determined by isometries and generalizes the Levi–Civita connection for the special case of Riemannian model spaces. The number of invariants needed to describe model spaces with the same tangent cone is in general greater than one, and these invariants are not necessarily related to the holonomy of the canonical connections.
Received 8 November 2017
Accepted 6 April 2018
Published 11 March 2021