YES(?,O(n^1))

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

Proof:
 Bounds Processor:
  bound: 1
  enrichment: match
  automaton:
   final states: {4,3,2}
   transitions:
    a1(5) -> 6*
    a1(7) -> 8*
    a1(6) -> 7*
    a0(1) -> 2*
    c0(1) -> 1*
    b0(1) -> 4*
    d0(1) -> 3*
    1 -> 5*
    8 -> 4*
  problem:
   
  Qed