During the reduction from CNF to 3-CNF, no new variables are introduced, and all clauses must already have exactly three literals before the conversion.

The reduction involves eliminating all clauses that contain more than three literals, and any clause with fewer than three literals is discarded.

In the reduction from CNF to 3-CNF, clauses with more than three literals are removed, but clauses with fewer than three literals are padded with repeated literals to ensure each clause has exactly three literals.

The CNF formula is transformed into a 3-CNF by replacing each literal with a corresponding set of three clauses, ensuring each clause contains exactly one literal.

In the reduction from CNF to 3-CNF, clauses with more than three literals are split by introducing new variables, and clauses with fewer than three literals are padded with repeated literals to ensure each clause has exactly three literals.