-Productions:

Nullable Variables:

Algorithm to determine Nullable Variables

Iteratively
if , and all symbols in
,
then

e.g.

1. 
2. because
3. because

Removal of -Productions
If , then add all productions
where

1. if is not nullable, then
2. if nullable, then is either or .
3. not all are .

e.g. P:

Since must be present.

P' :

- If L(G) does not contain , then G can be converted to equivalent G' without any -produtions.