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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Proof - value of p<br />
• First we find out <strong>the</strong> value of p.<br />
• Let G be a CFG for <strong>CFL</strong> L.<br />
• Let b be <strong>the</strong> maximum number of symbols in<br />
<strong>the</strong> right side of any rule in G.<br />
• So we know that in any parse tree of G a node<br />
can't have more than b children.<br />
• So if <strong>the</strong> height of a parsing tree for wL is h<br />
<strong>the</strong>n |w|< b h<br />
(h>log b |w|).<br />
A<br />
A 1 2 3 b<br />
<br />
1 2 3 b<br />
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