Clause Form

(all x) (Macintosh(x) -> UsesElectricity(x)

UsesElectricy(x) V Not Macintosh(x).

Any boolean formula can be put into conjunctive normal form (CNF).

If not Y then X and not Z.

Y or (X & not Z)

(Y or X & (Y or not Z)

(X V Y) & (Y V ~Z)

clauses: (X V Y), (Y V ~Z)

X, Y, and ~Z are called literals.