21 Dec
2015
21 Dec
'15
6:09 a.m.
At 03:26 AM 12/21/2015, Gareth McCaughan wrote: Theorem: a (merely) continuous function from R^n to R^n is determined
by countably many numbers.
Proof: specify its values at rational points (of which there are only countably many); its values elsewhere are determined by continuity.
That's a cool theorem! Does it have a name?