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 binunion : set set set const Sing : set set const Empty : set const Repl : set (set set) set const SetAdjoin : set set set const ordsucc : set set term eps_ = \x:set.binunion (Sing Empty) (Repl x \y:set.SetAdjoin (ordsucc y) (Sing (ordsucc Empty))) const SNoLt : set set prop term < = SNoLt infix < 2020 2020 axiom SNoLt_irref: !x:set.~ x < x const SNoLev : set set const SNo : set prop var x:set hyp Empty < x hyp SNo x hyp SNoLev x = Empty claim x != Empty