Module #5: Pushdown Automata (PDA's) and their relationship to CFL's

Objectives

1. Define a push-down automaton (pda) formally
   
2. Given an input string, show the transitions on a pda
   
3. Draw PDA's
   
4. Show the language of a grammar
   
5. Given a PDA, M, fin L such L = L(M)
   
6. Given a CFL language, L, find a PDA such that L = L(G)
   
7. Show various acceptance criteria are equivalent
   
8. Prove (or at least believe) that PDA's and CFG's are equivalent
   
9. Define deterministic PDA
   

   Topics

   1. Nondeterministic Pushdown Automata
      
   2. Converting PDA's to CFG's
      
   3. Converting CFG's to PDA's
      
   4. Closure Properties of Context-free Languages
      
   

   Background Material

   0. Texts

   Hopcroft, Motwani & Ullman: Chapter 6
   Kozen: Lectures 23, 24, & 25
   Sudkamp: Chapter 7 (Just 7.1-7.3)
   

   1. Wikepedia: Push-down Automaton
   1. Grahne Text Slides: Pages 181-224 and Tape
   2. Busch, Shiri & Grahne: Push-down Automata, part 1
   3. Busch, Shiri & Grahne: Push-down Automata, part 2
   4. Busch, Shiri & Grahne: Closure Properties of CFL's
   5. Pumping Lemma for CFL's
   6. Video of Intro to PDA's [vPOD]
   7. Video of PDA variants [vPOD]
   8. Video of Equivalence of CFL's and L(NPDA)'s [vPOD]
   9. Video of Pumping Lemma for CFL's [vPOD]
   

   Old Homeworks

   Homework Summer 05 [PDF]
   Solutions [DOC] [PDF]

   Homework 4 [pdf]

   Homework 4 Solutions [pdf]

   Homework 5 [pdf]

   Homework 5 Solutions [pdf]

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