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. Given a PDA, M, find L such L = L(M)
   
5. Given a CFL language, L, find a PDA such that L = L(G)
   
6. Believe that NPDA's and CFG's are equivalent
   
7. Define deterministic PDA
   

   Topics

   1. Nondeterministic Pushdown Automata
      
   2. Pumping Lemma for CFL's
   3. 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
   

   Old Homeworks

   Homework Fall 05 [PDF]
   Solutions [PDF]

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

   Homework [PDF]

   Homework Solutions [PDF]

   Use this tool to check your answers