Pushdown Automaton: CFL and the pumping lemma
Pushdown Automaton: CFL and the pumping lemma
Pushdown Automaton: CFL and the pumping lemma
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Intersection 1<br />
<strong>CFL</strong> are not closed under intersection.<br />
Proof: by contradiction<br />
L 1 ={a n b n c k |n,k>0}<br />
L 2 ={a k b n c n | n,k>0}<br />
Both L 1 <strong>and</strong> L 2 are <strong>CFL</strong> but<br />
L 1 L 2 = {a j b j c j | j>0} is not a <strong>CFL</strong>.<br />
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