The following statement [cannot][1] be proven in $\mathsf{ZFC}$: >> (S) : If $A, B$ are sets with $|A| < |B|$, then $2^{|A|} = |{\cal P}(A)| < |{\cal P}(B)| = 2^{|B|}$. Obviously, $\mathsf{GCH}$ implies (S). Does (S) imply $\mathsf{GCH}$ too? [1]: http://mathforum.org/kb/message.jspa?messageID=182924