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CHAPTER 10 / BASIC TECHNOLOGY OFTHE INTELLIGENT COMMUNICATION SYSTEM 1 1 7
FIGURE 10.7 Interpretation of V* 3 yP(x, y).
FIGURE 10.8 Interpretation of 3yVxP(x, y).
10.4.2 Clausal Form
An atomic formula or a negation of an atomic formula is called a literal. If a clause
C t(i = 1, 2,..., m) is composed of a disjunction of literals, then q xl, q x2,--',
4xn(Ci A C 2 A • • • A C m) is called a clausal form, where q is a quantifier V or 3 and
x l,x 2,...,x n are bound variables that appear in C } A C 2 A • • • A C m. C\ A C 2 A • • • A
C m is called a matrix.
Conversion from a logical expression to a clausal form is accomplished as
follows.
(1) Eliminate an equivalent or an implication:
(2) Move a negation to the front of an atomic formula:
