⊦ compl(f)(S)(x) ↔ ¬ f(λ x0. ¬ S(x0))(x)
¬ f(λ x0. ¬ S0(x0))(x), S0 ⊆ S, ∀ S, S0. S ⊆ S0 → f(S) ⊆ f(S0) ⊦ compl(f)(S)(x)
Used terms: x, S0, f