Before we learn more about particular types of types of canonical normal forms, we will introduce some auxiliary definitions and a lemma.
Let $\phi$ be a proposition with the Boolean variables $x_1,\ldots,x_n.$ * Every occurence of $x_i$ and/or its negation $\neg x_i$ in $\phi$ is called a literal. We denote a literal by $(\neg)x_i.$ * Every conjunction of literals $(\neg)x_1\wedge \ldots \wedge (\neg)x_n$ is called a minterm. * Every disjunction of literals $(\neg)x_1\vee \ldots \vee (\neg)x_n$ is called a maxterm.
Lemmas: 3 4
Proofs: 5 6