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

Proof:
 Bounds Processor:
  bound: 2
  enrichment: match
  automaton:
   final states: {3,2}
   transitions:
    c1(9) -> 10*
    c1(8) -> 9*
    a1(5) -> 6*
    a1(7) -> 8*
    a1(4) -> 5*
    a1(6) -> 7*
    b2(20) -> 21*
    b2(22) -> 23*
    a0(1) -> 2*
    b0(1) -> 3*
    c0(1) -> 1*
    1 -> 4*
    4 -> 20*
    5 -> 22*
    10 -> 21,7,3
    21 -> 7*
    23 -> 8*
  problem:
   
  Qed