On Jan 26, 2010, at 5:09 PM, Jeremy Bem wrote: > Why would someone prefer ZFC? [over ZC) One reason to consider: THEOREM. Every Borel set in the Euclidean plane = RxR, symmetric about the line y = x, contains or is disjoint from the graph of a Borel function from R into R. The above theorem is provable in ZFC but not in ZC. Harvey Friedman