YES

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

Proof:
 DP Processor:
  DPs:
   f#(f(a(),a()),x) -> f#(a(),f(a(),a()))
   f#(f(a(),a()),x) -> f#(f(a(),f(a(),a())),a())
   f#(f(a(),a()),x) -> f#(x,f(f(a(),f(a(),a())),a()))
  TRS:
   f(f(a(),a()),x) -> f(x,f(f(a(),f(a(),a())),a()))
  EDG Processor:
   DPs:
    f#(f(a(),a()),x) -> f#(a(),f(a(),a()))
    f#(f(a(),a()),x) -> f#(f(a(),f(a(),a())),a())
    f#(f(a(),a()),x) -> f#(x,f(f(a(),f(a(),a())),a()))
   TRS:
    f(f(a(),a()),x) -> f(x,f(f(a(),f(a(),a())),a()))
   graph:
    f#(f(a(),a()),x) -> f#(x,f(f(a(),f(a(),a())),a())) ->
    f#(f(a(),a()),x) -> f#(a(),f(a(),a()))
    f#(f(a(),a()),x) -> f#(x,f(f(a(),f(a(),a())),a())) ->
    f#(f(a(),a()),x) -> f#(f(a(),f(a(),a())),a())
    f#(f(a(),a()),x) -> f#(x,f(f(a(),f(a(),a())),a())) ->
    f#(f(a(),a()),x) -> f#(x,f(f(a(),f(a(),a())),a()))
   SCC Processor:
    #sccs: 1
    #rules: 1
    #arcs: 3/9
    DPs:
     f#(f(a(),a()),x) -> f#(x,f(f(a(),f(a(),a())),a()))
    TRS:
     f(f(a(),a()),x) -> f(x,f(f(a(),f(a(),a())),a()))
    Usable Rule Processor:
     DPs:
      f#(f(a(),a()),x) -> f#(x,f(f(a(),f(a(),a())),a()))
     TRS:
      
     Bounds Processor:
      bound: 1
      enrichment: match-dp
      automaton:
       final states: {4}
       transitions:
        f{#,1}(7,11) -> 4*
        f1(8,9) -> 10*
        f1(8,8) -> 9*
        f1(10,8) -> 11*
        a1() -> 8*
        f{#,0}(3,7) -> 4*
        f0(1,2) -> 2*
        f0(2,1) -> 2*
        f0(6,1) -> 7*
        f0(1,1) -> 5,2
        f0(1,5) -> 6*
        f0(2,2) -> 2*
        a0() -> 1*
        1 -> 3*
        2 -> 3*
      problem:
       DPs:
        
       TRS:
        
      Qed