“…In recent years a great deal of attention has been given to the characterisation of the weak-minimality for (Po) and (Pj) by employing various notions of derivatives for set-valued maps, see [2,3,4,7,8,11,12,13] and the references therein. A common strategy adopted in these works is to use direct arguments, based on the derivatives chosen for the set-valued maps involved, to verify a claim that the images of the derivatives do not intersect with certain open cones.…”