January 30

• Quiz 1
• Parser for a Finite Acceptor
• Sometimes trap states are not shown, simply implied
• Non-deterministic FA: see the different types of transitions
  • delta(state, character) notation vs. delta*(string) notation
  • a state might have more than one arc from a given character
  • a state might have a lambda on the transitions: no letter is consumed
  • when is a string accepted by an NFA? delta*(string) contains a state from F. (i.e. there exists a path that accepts the string)
  • Positives and negatives of NFA: easier: machines that either accept 3 a's or an even number greater than one.