The most important lemma in Topology | Urysohn Lemma | Part 1

In this video we prove Urysohn Lemma. Essential to prove Urysohn's metrisation theorem! The lemma says that if X is a normal space and A,B are two closed disjoin subsets of X, then there exists a continuous function that separates them..

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Timestamps in this video:
00:00 Introduction.
01:25 The Lemma.
02:40 The converse is trivial.
04:45 Idea for proof.
05:16 First part of the proof.
13:52 Summary of what we did.

#maths #topology #analysis