Week+6+-+Wiki+Question

=**Question 1**= =**Answer:**= Question 1a: in my opinion, we need to change it into conjunctive normal form, so, there must be a conjunction in the clauses. therefore, i'll use negation to make the disjunction into conjunction.

Question 1b:

It is proved that the inference in first-order logic is valid using resolution.

Question 1c: from the above table, we can prove that the inference is valid.

From the above table, it is shown that the inference is valid.
 * another answer from my opinion:

Chieng : He he... come comment your 1 c already, Do u still rem lecture time the example that we have?



We tried to prove by truth table rite? But we can't get all T T T T T T T T T T T T at the end. However, from the truth table, we can c that : when B Is T, no matter A is what, A V B is T. But negate B will be F, to let negate B V C to be T, C have to be T.

same case, when negate B is T, no matter C is what, negate B V C is T. but in this case B is F, to let A V B to be T, A have to be T. so, we can see that it depend on A and C actually to decide whether it's True or false, so the resolution is A V C. In question c, it's actually exactly the same. The only different is A, B, C change to P, Q ,R, isn't it? let see the picture below.



From the truth table above, we can c that : when Q Is T, no matter negate P is what, negate P V Q is T. But negate Q will be F, to let negate Q V R to be T, R have to be T.

same case, when negate Q is T, no matter R is what, negate Q V R is T. but in this case Q is F, to let negate P V Q to be T, negate P have to be T. so, we can see that it depend on negate P and R to decide whether it's True or false, so the resolution is negate P V R.

Question 1d:

=Question 2=



=Answer:=

p/s: carol: dear group member, we'll doing ques 1, ok? ^_^ chieng: Each of us please take one question, ok? First come first serve. Nick choo: Question 2 done by Choo Pei Ching, for question 2b will upload soon Chieng: Question 2 is extra for us already, 1 group only need do 1 question, but no wrong for do more right? ^ ^ Nick,2d CNF (conjunctive normal form) I think there is a mistake. Has to use N instead of U. He he ! Change it? Chieng: Choon see.... why u del my answer? sob sob... choon see:sory chieng, mis-press the button and i m not realize your answer is deleted d.Sorry lo..+_+ Boon ding: I done question 1.c. can please comment? ^_^

Name: Carolyne Alphonsus Tommy Chieng Lung Hei Ng Boon Ding Ng Choon See Choo Pei Ching