/sci/ - Science & Math

>>15136585
>>15136639
>>extract countably infinite subset of M, called it M' (<- do I need the axiom of choice for this?)
You do, yeah.

The proof works in principle but the writing is a bit awkward. You'd usually present it like this:
>we can choose a countable infinite subset of M
>hence we only need to prove the theorem for the naturals
>here's a proof for the naturals

Also
>>sort M' with the canonical ordering relation "<", such that (f(m1) = 1, f(m2) = 2,...)
Irrelevant and nonsensical.