const Repl : set (set set) set const Sep : set (set prop) set term ReplSep = \x:set.\p:set prop.Repl (Sep x p) const In : set set prop term iIn = In infix iIn 2000 2000 axiom SepI: !x:set.!p:set prop.!y:set.y iIn x -> p y -> y iIn Sep x p axiom ReplI: !x:set.!f:set set.!y:set.y iIn x -> f y iIn Repl x f claim !x:set.!p:set prop.!f:set set.!y:set.y iIn x -> p y -> f y iIn ReplSep x p f