MAYBE
Trs:
 {       D(t()) -> 1(),
  D(constant()) -> 0(),
     D(*(x, y)) -> +(*(y, D(x)), *(x, D(y))),
     D(+(x, y)) -> +(D(x), D(y)),
     D(-(x, y)) -> -(D(x), D(y))}
 Comment:
  We consider a duplicating trs.
  FAIL:
   Open