In CNF, restrictions are put on the length of right sides of
production, whereas in Greibach Normal Form (GNF), restrictions are
put on the positions in which terminals and variables can appear.
33. What is meant by Greibach Normal Form?
A CFG is said to be in Greibach Normal Form if all productions have
the form
A ax
→
where a T
∈ and x V
∈
* .
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Theory of Automata, Formal Languages and Computation