MAYBE
Time: 0.012

Problem:
 Equations:
  fAC(fAC(x3,x4),x5) -> fAC(x3,fAC(x4,x5))
  fAC(x3,x4) -> fAC(x4,x3)
  fAC(x3,fAC(x4,x5)) -> fAC(fAC(x3,x4),x5)
  fAC(x4,x3) -> fAC(x3,x4)
 TRS:
  g(0(),fAC(x,x)) -> x
  g(x,s(y)) -> g(fAC(x,y),0())
  g(s(x),y) -> g(fAC(x,y),0())
  g(fAC(x,y),0()) -> fAC(g(x,0()),g(y,0()))

Proof:
 Open