Question 1. For each of the following strings give a valid derivation, and a parse tree, for that string.
Question 2. Is the grammar unambiguous? Justify your answer.
Question 3
Applying this new pumping lemma can require the same sort of creative decisions as the one for
regular languages. Previously we showed this language was not regular:
Question 4
We mentioned earlier that the class of context-free languages is not closed under the
intersection operation.
Can you prove it now that we have some examples of non-context-free languages?
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