FOM: Reply to Shoenfield on Conservative Extensions

Joe Shipman shipman at
Mon Oct 5 11:50:16 EDT 1998

The result Steve sketched a proof of (and my query which provoked this)
concerned the conservativeness of ZFC over "ZF + Real Choice" for
sentences of second-order arithmetic, not (as you state) the
conservativeness of "ZF+RC" over ZF for sentences of second-order

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