Rules of inference and equivalence question?
s v r Premise
r -> ~q Premise
p -> q Premise
Prove: s v t
I was able to do the harder ones but not this one and its supposedly the easiest...
- SamwiseLv 75 years agoFavorite Answer
Using this reference set of rules of inference:
1. S v R
3. R -> ~Q
4. P -> Q
5. Q [4 and 1, modus ponens]
6. ~R [3 and 5, modus tollens]
7. R v S [1, commutation]
8. S [7 and 6, disjunctive syllogism]
9, S v T [8, addition]
You can count on the addition rule coming into play when you see a variable that wasn't anywhere in the premises.