const In : set set prop term iIn = In infix iIn 2000 2000 term Subq = \x:set.\y:set.!z:set.z iIn x -> z iIn y const Inj1 : set set axiom Inj1I2: !x:set.!y:set.y iIn x -> Inj1 y iIn Inj1 x const ordsucc : set set var x:set var y:set hyp !z:set.z iIn x -> Inj1 z = ordsucc z hyp x = ordsucc y claim y iIn x -> ordsucc y iIn Inj1 x