Unification

Predicate calculus rules are sometimes so general that we need to create specializations of them in order to perform resolution.

Suppose we have the rule

If x is a working automobile, then x has an engine.

P(x) -> Q(x)

and we have the fact

Tim’s Chevy is a working automobile

P(a)

These cannot immediately be resolved because P(x) and P(a) don’t quite match. They must be “unified.”

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