Here's a link to the proof I typed up for my problem set: https://www.sharelatex.com/project/534230c0234f079f3ce526fa?r=035466af&rs=ps&rm=d https://www.sharela

Here's a link to the proof I typed up for my problem set: https://www.sharelatex.com/project/534230c0234f079f3ce526fa?r=035466af&rs=ps&rm=d https://www.sharelatex.com/project/534230c0234f079f3ce526fa?... Theorem 1.10 states "If S andT are countable sets, the set S ×T ={(s,t) : s∈S,t∈T} is countable." and is proven using a diagonal argument.