YES(?,O(n^1))

Problem:
 f(x,x) -> f(a(),b())
 b() -> c()

Proof:
 Bounds Processor:
  bound: 2
  enrichment: match
  automaton:
   final states: {7,4,3}
   transitions:
    f0(1,2) -> 3*
    f0(7,1) -> 3*
    f0(2,1) -> 3*
    f0(7,7) -> 3*
    f0(2,7) -> 3*
    f0(1,1) -> 3*
    f0(1,7) -> 3*
    f0(7,2) -> 3*
    f0(2,2) -> 3*
    a0() -> 1*
    b0() -> 4*
    c0() -> 2*
    c1() -> 7*,2,4
    f1(1,4) -> 3*
    f1(1,7) -> 3*
    a1() -> 1*
    b1() -> 4*
    c2() -> 2,7*,4
  problem:
   
  Qed