Meromorphic Potentials and Smooth CMC Surfaces
  This work is based on the approach developed by J.~Dorfmeister, F.~Pedit and H.~Wu [GANG and KITCS preprint, Report KITCS94-4-1] to construct maps $\Phi:D\rightarrow R^3$, $D$ being the unit disk in $C$, whose images are surfaces of constant mean curvature. They start from certain meromorphic one forms, so called meromorphic potentials, which take values in a twisted loop algebra over $su(2)$. The authors give necessary and sufficient conditions on the meromorphic potential for the constructed map $\Phi$ to be an immersion. This revision corrects several misprints and minor TeX problems. 
J. Dorfmeister, G. Haak