The logic of the predicates whether the correct decision?

To prove the validity of using the method of resolutions:

No Republican or Democrat is not a socialist. Norman Thomas is a socialist. Therefore, he is not a Republican.

I decided the following:

P(x) = "x is a Republican"
Q(x) = "x - d"
S(x) = "x is a socialist"

F1: ∀x∀y∀z ( (P(x) v Q(y)) → !S(z) ) = (CNF) = ( !S(z) v !P(x) ) ^ ( !S(z) v !Q(y) )
F2: S(Norman Thomas)
-----------------------------------
R: !P(Norman Thomas)

Then mn-in clause:
{ !S(z) v !P(x)!S(z) v !Q(y), S(NT) P (NT) }

1) !S(z) v !P(x)
2) !S(z) v !Q(y)
3) S(NT)
4) P (NT)
-----------------
5) !P(NT) (combined 1 and 3)
6) F (connected 5 and 4)

because came to a contradiction, the original assumption was true.

Please tell me if this is the right decision or not (and how, then, should be resolved)
March 20th 20 at 11:42
0 answer

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