Solution

ID: past-exam-of-the-metric-spaces-and-complex-analysis-course-of-the-university-of-oxford/2021/5/a/iii/solution

Suppose were omitted by . Then
would be an entire function. The reverse triangle inequality gives as , so there. On a sufficiently large closed disk, is bounded by continuity and the extreme value theorem; outside it, the limit gives a bound. The Liouville theorem therefore makes constant, and the limit forces .
That is impossible, since is nonzero at every finite . No value can be omitted, and hence

New to topics? Read the docs here!