# Concept derivation guides

299 concept teaching guides, separate from the 36,000 individual question derivations.

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Concept guide



## [Compactness reduces separating neighborhoods to finitely many](/en/derivations/derivation-mko-compact-subset-closed-in-hausdorff-01/?from=%2Fen%2Fderivations%2F%3Fq%3Dmko-compact-subset-closed-in-hausdorff)

Prove a compact subset K of a Hausdorff space is closed.

A compact subset of a Hausdorff space is closed

derivation-mko-compact-subset-closed-in-hausdorff-01





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