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I I 2 INTELLIGENT COMMUNICATION SYSTEMS
10.3.2 Clausal Form
A literal is an atomic formula or a negation of an atomic formula. A disjunction of
a literal is considered a clause C,-, which is notated as follows:
A clausal form C is a conjunction of clauses, described as follows:
A logical expression is converted to a clausal form via the following operations.
(1) Eliminate an equivalent and an implication from a logical expression:
(2) Move a negation to the front of an atomic formula:
(3) Apply a distribution rule to a logical expression:
Here are some examples of how a clausal form is obtained from a logical ex-
pression by the operations just described.
Example 1:
