CORNERS IN NON-EQUIREGULAR SUB-RIEMANNIAN MANIFOLDS

摘要

We prove that in a class of non-equiregular sub-Riemannian manifolds corners are not length minimizing. This extends the results of [G.P. Leonardi and R. Monti, Geom. Funct. Anal. 18 (2008) 552-582]. As an application of our main result we complete and simplify the analysis in [ R. Monti, Ann. Mat. Pura Appl. (2013)], showing that in a 4-dimensional sub-Riemannian structure suggested by Agrachev and Gauthier all length-minimizing curves are smooth.