September 21

September 21 - CSCI 2670 Introduction to Theory of...

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CSCI 2670 Introduction to Theory of Computing September 21, 2005
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September 23, 2004 2 Agenda Yesterday Pushdown automata Today Quiz More on pushdown automata Pumping lemma for CFG’s
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September 23, 2004 3 Finite automata and PDA schematics State control a   a   b   b   State control a   a   b   b   x y FA PDA Stack:  Infinite  LIFO (last in  first out) device
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September 23, 2004 4 Definition of pushdown automaton A pushdown automaton is a 6-tuple (Q, Σ , Γ , δ ,q 0 ,F),  where Q, Σ , Γ , and F are all finite sets, and 1. Q is the set of states 1. Σ  is the input alphabet  2. Γ  is the stack alphabet  3. δ : Q  ×   Σ ε   ×   Γ ε    P(Q  ×   Γ ε ) is the transition  function 1. q 0    Q is the start state, and 2.  Q are the accept states.
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September 23, 2004 5 Strings accepted by a PDA Let w be a string in  Σ and P a PDA.  w is in L(P) iff  w can be written w=w 1 w
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This note was uploaded on 02/07/2011 for the course CS 501 taught by Professor Sm during the Spring '11 term at Indiana.

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September 21 - CSCI 2670 Introduction to Theory of...

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