YES
TRS:
 {f(a(), f(x, a())) -> f(a(), f(f(a(), x), f(a(), a())))}
 DP:
  Strict:
   {f#(a(), f(x, a())) -> f#(f(a(), x), f(a(), a())),
    f#(a(), f(x, a())) -> f#(a(), x),
    f#(a(), f(x, a())) -> f#(a(), f(f(a(), x), f(a(), a()))),
    f#(a(), f(x, a())) -> f#(a(), a())}
  Weak:
  {f(a(), f(x, a())) -> f(a(), f(f(a(), x), f(a(), a())))}
  EDG:
   {(f#(a(), f(x, a())) -> f#(a(), x), f#(a(), f(x, a())) -> f#(f(a(), x), f(a(), a())))
    (f#(a(), f(x, a())) -> f#(a(), x), f#(a(), f(x, a())) -> f#(a(), x))
    (f#(a(), f(x, a())) -> f#(a(), x), f#(a(), f(x, a())) -> f#(a(), f(f(a(), x), f(a(), a()))))
    (f#(a(), f(x, a())) -> f#(a(), x), f#(a(), f(x, a())) -> f#(a(), a()))}
   SCCS:
    Scc:
     {f#(a(), f(x, a())) -> f#(a(), x)}
    SCC:
     Strict:
      {f#(a(), f(x, a())) -> f#(a(), x)}
     Weak:
     {f(a(), f(x, a())) -> f(a(), f(f(a(), x), f(a(), a())))}
     SPSC:
      Simple Projection:
       pi(f#) = 1
      Strict:
       {}
      Qed