[Thm S1]: Sequentially Compact then Boudned

設 $S\subseteq(M,d)$ 是 sequentially compact 則 $S$ 必有界

[Thm C1]: Compact then Boudned

設 $K\subseteq(M,d)$ 是 compact 則 $K$ 必有界

[Thm S2]: Sequentially Compact then Closed

設 $S\subseteq(M,d)$ 是 sequentially compact 則 $S$ is closed

[Thm C2]: Compact then Closed

設 $K\subseteq(M,d)$ 是 sequentially compact 則 $K$ is closed