On the Directonal Derivative Sets and Differentials of the Set Valued   Maps
  In this paper directional derivative sets and differentials of a given set valued map are studied. Relations between the set valued map and compact subsets of the directional derivative sets of the given map are investigated. Upper and lower contingent cones of some plane sets are calculated. 
Serpil Altay, Nihal Ege, Anar Huseyin, Nesir Huseyin
math.FA