Deriving rules
p ? q, q ? r ? p ? r
If John has stolen a bike, then he is a thief
If John is a thief, then he is punishable
?
If John has stolen a bike, then he is punishable
p ? (q ? r), p ? q ? r
If thieves are punishable, then (if John is a thief, then he is punishable)
Thieves are punishable
?
If John is a thief, he is punishable