MAYBE
Time: 0.011

Problem:
 Equations:
  timesAC(timesAC(x1,x2),x3) -> timesAC(x1,timesAC(x2,x3))
  timesAC(x1,x2) -> timesAC(x2,x1)
  timesAC(x1,timesAC(x2,x3)) -> timesAC(timesAC(x1,x2),x3)
  timesAC(x2,x1) -> timesAC(x1,x2)
 TRS:
  p(s(x)) -> x
  fac(0()) -> s(0())
  fac(s(x)) -> timesAC(s(x),fac(p(s(x))))

Proof:
 Open