¬(∀ S. compl(f)(S) ⊆ S → S(x)) ⊦ ∃ S. S ⊆ f(S) ∧ S(x)
∃ S. S ⊆ f(S) ∧ S(x) ⊦ ¬(∀ S. compl(f)(S) ⊆ S → S(x))