Paper 3, Section II, H

Riemann Surfaces
Part II, 2014

State the Uniformization Theorem.

Show that any domain of C\mathbb{C} whose complement has more than one point is uniformized by the unit disc Δ.\Delta . [You may use the fact that for C\mathbb{C}_{\infty} the group of automorphisms consists of Möbius transformations, and for C\mathbb{C} it consists of maps of the form zaz+bz \mapsto a z+b with aCa \in \mathbb{C}^{*} and bCb \in \mathbb{C}.

Let XX be the torus C/Λ\mathbb{C} / \Lambda, where Λ\Lambda is a lattice. Given pXp \in X, show that X\{p}X \backslash\{p\} is uniformized by the unit discΔ\operatorname{disc} \Delta.

Is it true that a holomorphic map from C\mathbb{C} to a compact Riemann surface of genus two must be constant? Justify your answer.