Unformatted text preview: Eliminate all ↔ connectives
(P ↔ Q) rewritten as ((P → Q) ∧ (Q → P)) 2. Eliminate all → connectives
(P → Q) rewritten as (~P v Q) 3. Reduce the scope of each negation symbol to a single predicate
~~P rewritten as P
~~P
~(P v Q) rewritten as ~P ∧ ~Q
~(P ∧ Q) rewritten ~P v ~Q
~(∀x)P rewritten as (∃x)~P
~(∃x)P rewritten as (∀x)~P 4. Standardize variables: rename all variables so that each quantifier has
its own unique variable name CS 460, Session 18 13 Skolemization Step 5 – Complicated by Quantifiers CS 460, Session 18 14 Final Steps of Converting sentences to clausal form
6. Remove universal quantifiers by (1) moving them all to the left end;
(2) making the scope of each the entire sentence; and (3) dropping
the “prefix” part
Ex: (∀x)P(x) ==> P(x) 7. Put into c...
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This note was uploaded on 02/19/2014 for the course CSCI 460 taught by Professor Narayanaswamy during the Spring '08 term at USC.
 Spring '08
 Narayanaswamy
 Artificial Intelligence

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