Let $[a,b]\subseteq \mathbb R$. As we know, it is compact. This is a very important result. However, the proof for the result may be not familiar to us. Here I want to collect the ways to prove $[a,b]$ is compact.
Thanks for your help and any link.
Proposal: Add the tag claim-verification
Maybe not the best example, but my question here is about verifying a claim, not a solution or a proof. I don’t find any other fitting tags for such a question.