Some Basic Discrete Math Definition

A variable is a logical variable like $x$,$y$, $p$, $q$.

A literal is either a logical variable or the negation of a logical variable. For example, $\neg x, y, \neg p$ are all literals.

A clause is an ``or '' of literals. For example $x \lor y \lor \neg p$ is a clause.

A term is an `` and'' of literals. For example $x \land y \land \neg p$ is a term.

The width of a clause/term is the number of literals in it. A clause/term of width 1 is a single literal.

A formula is in conjunctive normal form (CNF) if it is an ``and'' of clauses.

A formula is in disjunctive normal form (DNF) if it is an ``or'' of terms.

The size of a CNF/DNF is the number of clauses/terms in it. A CNF/DNF of size 1 is a single clause/term.

Two formulas $\varphi, \psi$ are called equivalent if $\varphi \iff \psi$.