Derivable Behaviors (Theorems)

• If (n = Q.size()) is followed by k push operations then n + k = Q.size()
• If (n = Q.size()) is followed by k pop operations then n - k = Q.size()

  in particular, k <= n
• The first element pushed onto Q (of those still in Q) is the front of Q
• Q.pop() removes the front element of Q
• Any two queues of type T are isomorphic