My solution: So I had points taken off. Not sure why. The answer provided was: W

Question

My solution:

So I had points taken off. Not sure why.

The answer provided was:

We want to show that the conditional statement ¬R(a) P (a) is true for all a in the domain; the desired conclusion then follows by universal generalization. Thus we want to show that if ¬R(a) is true for a particular a , then P (a) is also true. For such an a, universal modus tollens applied to the second premise gives us ¬(¬P (a) Q(a)). By rules from propositional logic, this gives us P (a) ¬Q(a). By universal generalization from the first premise, we have P (a) Q(a). Now by resolution we can conclude P (a) P (a) which is logically equivalent to P (a), as desired.

mmm...okay, but what is wrong with mine?

Explanation / Answer

I don't see any prob with your solution... May be your instructor found your solution lengthy and deducted marks...

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