TheoremBase

A Closed Totally Bounded Subset of a Complete Metric Space is Compact

A closed, totally bounded subset of a complete metric space is sequentially compact and compact.

Statement

In the setting of The Real Numbers: Standing Notation and Background, let (X,d)(X,d) be a complete metric space, let Td\mathcal{T}_{d} be the collection of subsets of XX that are open in (X,d)(X,d), a topology on XX by Metric Open Sets Form a Topology, and let K⊆XK\subseteq X be closed in (X,Td)(X,\mathcal{T}_{d}) and totally bounded in (X,d)(X,d). Then the following hold.

1. (Sequential compactness) KK is sequentially compact in (X,d)(X,d): every sequence in KK has a subsequence converging in (X,d)(X,d) to a point of KK.

2. (Compactness) KK is compact in (X,Td)(X,\mathcal{T}_{d}).

Proofs

Log in to submit a proof.

Loading...

Citations

Loading…

Dependencies

Loading…

Related

0 relations

Curated associations between results. These are editable and subjective — they do not replace the dependency graph, which is derived from the references in the text.

No relations recorded yet.

Comments

Log in to comment.

Loading…