To prove that a language is not context-free

To prove that a language is regular

To prove that a language is context-free

To prove that a language is context-sensitive

A → α A → β

A → βA' A' → αA' | ε

A → αA | β A' → ε’

A → ε A' → αA

Introducing new non-terminals to eliminate left recursion

Reordering production rules

Replacing terminal symbols with non-terminals

Replacing non-terminals with terminal symbols

A → aB

A → BC

All the mentioned

A → BCD

Backus-Naur Form

Greibach Normal Form

Any form

Chomsky Normal Form

It makes the grammar ambiguous

It increases the number of production rules

It simplifies the grammar for parsing algorithms

Each production has at most one non-terminal on the right-hand side

Each production has at most one terminal on the left-hand side

Each production is either of the form A → BC or A → a

Each production is either of the form A → aB or A → a

None of the above

Non-terminals

Terminals

Both terminals and non-terminals