%0 Journal Article %A Bourgain, Jean %A Brezis, Haim %A Mironescu, Petru %T $H^{1/2}$ maps with values into the circle : minimal connections, lifting, and the Ginzburg-Landau equation %J Publications Mathématiques de l'IHÉS %D 2004 %P 1-115 %V 99 %I Springer %U http://archive.numdam.org/articles/10.1007/s10240-004-0019-5/ %R 10.1007/s10240-004-0019-5 %G en %F PMIHES_2004__99__1_0