%0 Journal Article %A Luis Caffarelli %A Robert J. McCann %T Free boundaries in optimal transport and Monge-Ampère obstacle problems %J Annals of mathematics %D 2010 %P 673-730 %V 171 %N 2 %U http://geodesic.mathdoc.fr/articles/10.4007/annals.2010.171.673/ %R 10.4007/annals.2010.171.673 %G en %F 10_4007_annals_2010_171_673