specification
sorts elem;
predicates
. ≪ . : elem × elem;
variables
iHP : elem → bool;
a : elem;
a0 : elem;
a1 : elem;
axioms
trans: a ≪ a0 ∧ a0 ≪ a1 → a ≪ a1;
used for: lf, f;
wellfounded: ∀ a. (∀ a0. a0 ≪ a → iHP(a0)) → iHP(a) ⊦ iHP(a);
end specification