3. Use a truth table to show that p ∧ ¬q → r ↔ ¬(p ∧ q) ∨ r holds.
[12 marks]
4. Prove the following, using the semantic equivalences given on the slides of logic lecture 3. In each step, apply only one rule once and state the name of the rule.
a ∧ (p → q) ∧ (p → ¬q) → (p ∧ ¬q) → (p → q) ∧ (p → ¬q)
[18 marks] [18 marks]