Lecture 5 Part 2 (Logic)

How is the existential quantifier defined in terms of the universal quantifier?

1. A.∃x P(x) ≡ ∀x P(x)
2. B.∃x P(x) ≡ ¬∀x ¬P(x)
3. C.∃x P(x) ≡ ∀x ¬P(x)
4. D.∃x P(x) ≡ ¬∀x P(x)