1. Stdnt id: roll no.

2. Ambiguous CFG: The CFG is Said to be Ambiguous if There exist at least one word of it’s language that it can be generated by the Different production trees.

3. Example: Consider The Following CFG S as|Sa|a The Words aan can be generated by the Following three different Trees
Examples: S S S a a S a S S a S S a S a a a a

4. Thus the above CFG is ambiguous, while CFG, S aS|a is not ambiguous as Neither the word aaa nor any other word can be Derived from more then one Production Trees. The derivation tree for aaa is as follows. S S a a S a