4.I.2F

Topics in Analysis
Part II, 2008

(a) State Runge's theorem on uniform approximation of analytic functions by polynomials.

(b) Suppose ff is analytic on

Ω={zC:z<1}\{zC:Im(z)=0,Re(z)0}.\Omega=\{z \in \mathbf{C}:|z|<1\} \backslash\{z \in \mathbf{C}: \operatorname{Im}(z)=0, \operatorname{Re}(z) \leqslant 0\} .

Prove that there exists a sequence of polynomials which converges to ff uniformly on compact subsets of Ω\Omega.