Pushdown Automata - Hampden-Sydney College
Pushdown Automata - Hampden-Sydney College
Pushdown Automata - Hampden-Sydney College
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The Grammar Rules (Group 1)<br />
<strong>Pushdown</strong><br />
<strong>Automata</strong> -<br />
Equivalence<br />
to CFGs<br />
Robb T.<br />
Koether<br />
Homework<br />
Review<br />
Equivalence<br />
of PDAs and<br />
CFGs<br />
Proof ⇒<br />
Proof ⇐<br />
Long Example<br />
Short<br />
Example<br />
Assignment<br />
Example (Convert a PDA to a CFG)<br />
We may eliminate all rules with variables that represent<br />
impossible situations.<br />
A pq → A pp A pq A qq → A qp A pq<br />
A pq → A pq A qq A qq → A qq A qq<br />
A pq → A pr A rq A qq → A qr A rq<br />
A pr → A pp A pr A qr → A qp A pr<br />
A pr → A pq A qr A qr → A qq A qr<br />
A pr → A pr A rr A qr → A qr A rr
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