unit productions, or any λ-productions. But it is not minimal since S → aa
is an equivalent grammar.
Section 6.2
5. First we must eliminate λ-productions. This gives
This has introduced a unit-production, which is not acceptable in the
construction of Theorem 6.6. Removal of this unit-production is easy.
We can now apply the construction and get
and
8. Consider the general form for a production in a linear grammar
Introduce a new variable V 1 with the productions