const In : set set prop term iIn = In infix iIn 2000 2000 const real : set const SNo : set prop axiom real_SNo: !x:set.x iIn real -> SNo x const CSNo_Im : set set const SNo_pair : set set set axiom CSNo_Im2: !x:set.!y:set.SNo x -> SNo y -> CSNo_Im (SNo_pair x y) = y claim !x:set.x iIn real -> !y:set.y iIn real -> CSNo_Im (SNo_pair x y) = y