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The '''Urysohn lemma''' states:
The '''Urysohn lemma''' states:
<blockquote>
<blockquote>
If '''A''', '''B''' are 2 disjoint, closed subsets of a [[normal space]] '''X''', then there exist a [[continuous function]] '''f:X->[0,1]''' such that '''f(A)''' = 0 and '''f(B)''' = 1. The converse also hold.
If '''A''', '''B''' are 2 disjoint, closed subsets of a [[normal space]] '''X''', then there exist a [[continuous function]] '''f:X -> [0,1]''' such that '''f(A)''' = 0 and '''f(B)''' = 1.
</blockquote>
</blockquote>
The converse of the Urysohn lemma also holds.
[[category: Topology]]
[[category: Topology]]