The Oka principle for multivalued sections of ramified mappings

英文摘要：

In this paper we establish a basic version of the Oka principle for multivalued sections of ramified holomorphic maps h from a complex manifold Z onto a Stein manifold X. If the ramification locus of h projects into a closed complex subvariety X' of X and if h admits a fiber dominating spray over a small neighborhood of any point in X\X' then any multivalued continuous section of h which is holomorphic in a neighborhood of X' and unramified in X\X' can be homotopically deformed to a global holomorphic multivalued section. The corresponding results for sections of unramified submersions were established by Gromov (Oka's principle for holomorphic sections of elliptic bundles, J. Amer. Math. Soc. 2, 851-897 (1989)) and Forstneric and Prezelj (Math. Ann., to appear).