Among the following which is not a horn clause?

Among the following which is not a horn clause?

    • p
    • Øp V q
    • p → q
    • p → Øq
...

Horn Clause

The definite clause language does not allow a contradiction to be stated. However, a simple expansion of the language can allow proof by contradiction.

An integrity constraint is a clause of the form

    false←a1∧...∧ak.

where the ai are atoms and false is a special atom that is false in all interpretations.

A Horn clause is either a definite clause or an integrity constraint. That is, a Horn clause has either false or a normal atom as its head.

Integrity constraints allow the system to prove that some conjunction of atoms is false in all models of a knowledge base - that is, to prove disjunctions of negations of atoms. Recall that ¬p is the negation of p, which is true in an interpretation when p is false in that interpretation, and p∨q is the disjunction of p and q, which is true in an interpretation if p is true or q is true or both are true in the interpretation. The integrity constraint false←a1∧...∧ak is logically equivalent to ¬a1∨...∨¬ak.

Your can read more here with examples.

If you think above Mcq is wrong then please leave us comment with correct answers!

Leave comment below, Write your comment, Reply with your comment