UGC-NET | UGC NET CS 2015 Jun – III | Question 24

Which one of the following is true?
(A) The resolvent of two Horn clauses is not a Horn clause
(B) The resolvent of two Horn clauses is a Horn clause
(C) If we resolve a negated goal G against a fact or rule A to get clause C then C has positive literal or non-null goal
(D) If we resolve a negated goal G against a fact or rule A to get clause C then C has positive literal or null goal

Answer: (B)
Explanation:

The resolvent of two Horn clauses is not a Horn clause. False

The resolvent of two Horn clauses is a Horn clause. True

If we resolve a negated goal G against a fact or rule A to get clause C then C has positive literal or non-null goal. False

If we resolve a negated goal G against a fact or rule A to get clause C then C has positive literal or null goal. False

So, option (B) is correct.
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