Ginzburg-Landau minimizers from $\mathbb{R}^{n+1}$ to $\mathbb{R}^n$ and minimal connections Etienne Sandier 74G5574G6535Q6035J55Ginzburg-Landau modelelliptic systemsenergy minimization Indiana University Mathematics Journal 2001 text pdf 10.1512/iumj.2001.50.1751 10.1512/iumj.2001.50.1751 en Indiana Univ. Math. J. 50 (2001) 1807 - 1844 state-of-the-art mathematics http://iumj.org/access/