The sign for downward picking is V but it is only shown when the indication is needed. Usually you seldom start with a upward picking. Thus upward pickings are executed following downward pickings and must be given along the same root or with the same entry angle as downward pickings. Naturally upward pickings are not given by apoyando technique, while so downward pickings are. This is because, when picking upwards, we do not conclude the motion by resting on the string on top of the one recently played, hence the apoyando technique is specifically for downward picking.