Problem:
 a(x1) -> b(x1)
 a(a(b(c(x1)))) -> b(c(c(a(a(a(x1))))))

Proof:
 Bounds Processor:
  bound: 1
  enrichment: match
  automaton:
   final states: {3}
   transitions:
    b1(6) -> 7*
    b1(8) -> 9*
    a0(2) -> 3*
    a0(1) -> 3*
    b0(2) -> 1*
    b0(1) -> 1*
    c0(2) -> 2*
    c0(1) -> 2*
    1 -> 6*
    2 -> 8*
    7 -> 3*
    9 -> 3*
  problem:
   
  Qed