MAYBE
Time: 0.018

Problem:
 Equations:
  
 TRS:
  plusAC(x,0()) -> x
  plusAC(x,s(y)) -> s(plusAC(x,y))
  sumAC(nil(),nil()) -> 0()
  sumAC(cons(x,xs),nil()) -> plusAC(x,sumAC(xs,nil()))
  sumAC(nil(),cons(x,xs)) -> plusAC(x,sumAC(nil(),xs))
  sumAC(cons(x,xs),cons(y,ys)) -> plusAC(plusAC(x,y),sumAC(xs,ys))

Proof:
 Open