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 ordinal : set prop const SNo : set prop const SNoLev : set set const ordsucc : set set const SNoLe : set set prop term <= = SNoLe infix <= 2020 2020 axiom ordinal_SNoLev_max_2: !x:set.ordinal x -> !y:set.SNo y -> SNoLev y iIn ordsucc x -> y <= x var x:set var y:set hyp ordinal x hyp ordinal y hyp x iIn ordsucc y hyp SNo x claim SNoLev x = x -> x <= y