A determiner has the type possessive if it has the feature number of possessor. The other types of determiners do not have this feature. The possessive determiner establishes a relation between on the one hand an object which it determines and its possessor on the other.
Test:
Given X a determiner, If X has Pos=sg or Pos=pl, and pers=1 or pers=2 or pers=3, then X is a possessive determiner.
Examples: