const Repl : set (set set) set const Inj1 : set set term Inj0 = \x:set.Repl x Inj1 const In : set set prop term iIn = In infix iIn 2000 2000 axiom ReplE: !x:set.!f:set set.!y:set.y iIn Repl x f -> ?z:set.z iIn x & y = f z claim !x:set.!y:set.y iIn Inj0 x -> ?z:set.z iIn x & y = Inj1 z