Hyperbolic Components in Exponential Parameter Space

Abstract

We discuss the space of complex exponential maps $\Ek\colon z\mapsto e^{z}+\kappa$. We prove that every hyperbolic component $W$ has connected boundary, and there is a conformal isomorphism $\Phi_W\colon W\to\half^-$ which extends to a homeomorphism of pairs $\Phi_W\colon(\ovl W,W)\to(\ovl\half^-,\half^-)$. This solves a conjecture of Baker and Rippon, and of Eremenko and Lyubich, in the affirmative. We also prove a second conjecture of Eremenko and Lyubich.