Regular and limit sets for holomorphic correspondences
Volume 167 / 2001
Abstract
Holomorphic correspondences are multivalued maps $f={\widetilde Q}_+{\widetilde Q}_-^{-1}:Z \rightarrow W$ between Riemann surfaces $Z$ and $W$, where ${\widetilde Q}_-$ and ${\widetilde Q}_+$ are (single-valued) holomorphic maps from another Riemann surface $X$ onto $Z$ and $W$ respectively. When $Z=W$ one can iterate $f$ forwards, backwards or globally (allowing arbitrarily many changes of direction from forwards to backwards and vice versa). Iterated holomorphic correspondences on the Riemann sphere display many of the features of the dynamics of Kleinian groups and rational maps, of which they are a generalization. We lay the foundations for a systematic study of regular and limit sets for holomorphic correspondences, and prove theorems concerning the structure of these sets applicable to large classes of such correspondences.