const In : set set prop term iIn = In infix iIn 2000 2000 const ReplSep : set (set prop) (set set) set axiom ReplSepE: !x:set.!p:set prop.!f:set set.!y:set.y iIn ReplSep x p f -> ?z:set.z iIn x & p z & y = f z claim !x:set.!p:set prop.!f:set set.!y:set.y iIn ReplSep x p f -> !P:prop.(!z:set.z iIn x -> p z -> y = f z -> P) -> P