Problem 12. Suppose pis a Boolean variable. Prove that p1npF 1. Hint. p^+ Give a Hilbert-style proof and use the axiom of "golden rule followed by equa- nimity. problem 13. Write a Hilbert stole area Helent atele mroof for 1 - R L A B. Hint T. + Problem 12. Suppose pis a Boolean variable. Prove that p1npF 1. Hint. p^+ Give a Hilbert-style proof and use the axiom of "golden rule followed by equa- nimity. problem 13. Write a Hilbert stole area Helent atele mroof for 1 - R L A B. Hint T. +