1. Prove that the set {∨,∧, ¬} is universal. (Hint: once you’ve done Exercise 2., all you have to do is show that you can express ⇒ using {∨,∧, ¬}.) 4.68 Prove that {∨, ¬} and {∧, ¬} are both...

1. Prove that the set {∨,∧, ¬} is universal. (Hint: once you’ve done Exercise

2., all you have to do is show that you can express ⇒ using {∨,∧, ¬}.) 4.68 Prove that {∨, ¬} and {∧, ¬} are both universal