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Math and science::Analysis

Heine-Borel Theorem

Heine-Borel Theorem for \( \mathbb{R} \)

A set \( K \subset \mathbb{R} \) is compact iff it is closed and bounded.

If you have forgotten some of the formulations of compactness, here is a recap of one:

Compactness

A set \( K \subseteq \mathbb{R} \) is compact iff every sequence in \( K \) has a subsequence that converges to a limit that is also in \( K \).


Heine-Borel Theorem, proof

Below is a copy of Abbott's proof:


Source

Abbott, p84