Page 78 - DCAP506_ARTIFICIAL_INTELLIGENCE

Artificial Intelligence

Notes Eliminate  rewriting P  Q as P  Q
Use DeMorgans laws to push  inwards:
rewrite  (P  Q) as P  Q
rewrite  (P  Q) as P  Q

Eliminate double negations: rewrite P as P
Use the distributive laws to get CNF:
rewrite (P  Q)  R as (P  R)  (Q R)
rewrite (P  Q)  R as (P  R)  (Q  R)

Example:
(P  (Q  R))

(P (Q  R))
 P  (Q  R)
 P  (Q   R)
P (Q   R)

Two clauses: P, Q  R

5.4.2 Resolution Rule of Inference

Figure 5.4: Resolution Rule

where B is a propositional letter and A and C are clauses (possibly empty) A(“C is the resolvent of
the two clauses.

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