Principal Conjunctive Normal Form

Principal Conjunctive Normal form : A formula α is in principle conjugate normal form if α is a product of max terms. For obtaining the principle conjunctive normal form of α we can construct the principle disjunctive normal form of α ¬ and apply negation.
Example: Obtain a conjunctive normal form of

1) Consider

Hence, this is the required conjunctive normal form.

The principal conjugate normal form of α is

2)

Since, we know that

Which is required conjunctive normal form.