a1 LE2i, CNRS UMR5158, Université de Bourgogne, 9 avenue Alain Savary - BP 47870, 21078 Dijon Cedex, France.
a2 SISSA, via Beirut 2-4, 34014 Trieste, Italy. firstname.lastname@example.org; email@example.com
Fix two points and two directions (without orientation) of the velocities in these points. In this paper we are interested to the problem of minimizing the cost
along all smooth curves starting from x with direction η and ending in with direction . Here g is the standard Riemannian metric on S 2 and is the corresponding geodesic curvature. The interest of this problem comes from mechanics and geometry of vision. It can be formulated as a sub-Riemannian problem on the lens space L(4,1). We compute the global solution for this problem: an interesting feature is that some optimal geodesics present cusps. The cut locus is a stratification with non trivial topology.
(Received May 30 2008)
(Online publication December 19 2008)
Mathematics Subject Classification: