YES(?,O(n^1))

Problem:
 a(b(a(x))) -> b(a(b(x)))

Proof:
 Bounds Processor:
  bound: 1
  enrichment: match
  automaton:
   final states: {3}
   transitions:
    b1(10) -> 11*
    b1(12) -> 13*
    b1(8) -> 9*
    a1(9) -> 10*
    a0(3) -> 3*
    b0(3) -> 3*
    3 -> 8*
    9 -> 12*
    11 -> 10,3
    13 -> 9*
  problem:
   
  Qed