Question: let px qx rx and sx y be propositional functions...
Let P(x), Q(x), R(x), and S(x, y) be propositional functions. For each proposition below, give a logically equivalent proposition that uses only the universal quantifier ∀ and the logical connectives ¬ and ∧.
(a) ∃x (P(x) → Q(x))
(b) ∃x (¬Q(x) ↔ (P(x) ∧ R(x)))
(c) ∀x∃y ((S(x, y) ∧ Q(x)) → (R(x) ∨ R(y)))