From what we just saw in the previous example, we can generate a set of rules used to transform quantifiers: ∃xϕ(x)≡¬¬∃xϕ(x)≡¬∀x¬ϕ(x) ∀xϕ(x)≡¬¬∀xϕ(x)≡¬∃x¬ϕ(x)