title: what is the length of a language that contains epsilon?
body: <p>1, I have an NFA that can recognize two words, "aa" and "epsilon".
  So the language L1 this NFA recognizes is a set {aa, epsilon}.
  What is the length of this language?
  Is |L1| = 1? or |L1| = 2?</p>
  
  <p>2, Assuming I have another NFA that can recognize one word "aa".
  So the language L will be a set {aa}
  In formal language, epsilon belongs to every language.
  Thus in fact L2 contains epsilon, that is a set {aa, epsilon}
  So what is the lenght of this language L2? 1 or 2?</p>
  
  <p>Thanks</p>