HOMEWORK 1
- Show p =β q,r =β s ` p β§ r =β q β§ s is valid.
- Show (p β§ q) β¨ (p β§ r) ` p β§ (q β¨ r) is valid.
- Show p β§ q =β r ` (p =β r) β¨ (q =β r) is valid.
- Show p =β q `Β¬p β¨ q is valid.
- Show ` (p =β q) β¨ (q =β r) is valid.



