MAYBE
MAYBE
TRS:
 {
       f(true(), x, y, z) -> del(.(y, z)),
      f(false(), x, y, z) -> .(x, del(.(y, z))),
  =(.(x, y), .(u(), v())) -> and(=(x, u()), =(y, v())),
        =(.(x, y), nil()) -> false(),
        =(nil(), .(y, z)) -> false(),
          =(nil(), nil()) -> true(),
       del(.(x, .(y, z))) -> f(=(x, y), x, y, z)
 }
 DUP: We consider a duplicating system.
  Trs:
   {
         f(true(), x, y, z) -> del(.(y, z)),
        f(false(), x, y, z) -> .(x, del(.(y, z))),
    =(.(x, y), .(u(), v())) -> and(=(x, u()), =(y, v())),
          =(.(x, y), nil()) -> false(),
          =(nil(), .(y, z)) -> false(),
            =(nil(), nil()) -> true(),
         del(.(x, .(y, z))) -> f(=(x, y), x, y, z)
   }
  Fail