Paper 3, Section I, G

Topics in Analysis
Part II, 2014

State Runge's theorem about uniform approximation of holomorphic functions by polynomials.

Let R+C\mathbb{R}_{+} \subset \mathbb{C} be the subset of non-negative real numbers and let

Δ={zC:z<1}.\Delta=\{z \in \mathbb{C}:|z|<1\} .

Prove that there is a sequence of complex polynomials which converges to the function 1/z1 / z uniformly on each compact subset of Δ\R+\Delta \backslash \mathbb{R}_{+}.