Partial H\"older continuity for Q-valued energy minimizing maps

Abstract

We consider multivalued maps between $\Omega \subset \mathbb{R}^N$ open ($N \ge 2$) and a smooth, compact Riemannian manifold $\mathcal{N}$ locally minimizing the Dirichlet energy. An interior partial H\"older regularity result in the spirit of R. Schoen and K. Uhlenbeck is presented. Consequently a minimizer is H\"older continuous outside a set of Hausdorff dimension at most $N-3$. F. Almgren's original theory includes a global interior H\"older continuity result if the minimizers are valued into some $\mathbb{R}^m$. It cannot hold in general if the target is changed into a Riemannian manifold, since it already fails for "classical" single valued harmonic maps.