5 Mar
2009
5 Mar
'09
7:29 a.m.
Am Donnerstag, 5. März 2009 13:09 schrieb Peter Verswyvelen:
Ha. There's even a wiki page on the paradoxes of set theory http://en.wikipedia.org/wiki/Paradoxes_of_set_theory
If I recall correctly, a math professor once told me that it is not yet proven if the cardinality of the power set of the natural numbers is larger or smaller or equal than the cardinality of the real numbers... But that is many many years ago so don't shoot me if I'm wrong :)
In standard NBG set theory, it is easy to prove that card(P(N)) == card(R).