4. (10 marks) Prove that the class of context-free languages are not closed under complementation.
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Step 2: One way to approach this is to use the pumping lemma for context-free languages. The pumping lemma states that for any context-free language L, there exists a pumping length p such that any string s in L with |s| ≥ p can be divided into five parts, s = Show more…
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