statement theorem
Compact Hausdorff spaces are normal
Statement
Let be a compact space that is Hausdorff. Then is normal.
Remarks
Proof sketch: closed subsets of are compact, by closed subsets of a compact set are compact. In a Hausdorff space, a point and a disjoint compact set have disjoint open neighbourhoods. A second use of compactness separates two disjoint compact sets. With Urysohn's lemma, this shows that compact Hausdorff spaces have many continuous real functions.
Explanations
L1 human
In a compact Hausdorff space, you first separate points by open sets, and then compactness lets you combine finitely many of these choices. The result separates any two disjoint closed sets.
What this node needs for W1
- an inventory row: the row of the inventory that the node accounts for (0 of 1)
The writing levels say how complete the text of a node is. They do not measure its truth.
Sources
- Web https://en.wikipedia.org/wiki/Normal_space, Examples of normal spaces
What links here
No node links to this node yet.