Anyone have a sensible word to finish the title above? I'm creating a semantic web, and some of the flip-sides to directional relationships are hard to track down due to their scarce usage. The specific consumer of this relationship, so far, is a technology tree. Other examples of relationships:
Non-directional relationship: Joe is a friend of Bob, Bob is a friend of Joe
Directional relationship: Sean is a father of Jill, Jill is a daughter of Sean
For the relationship in question I'm considering "contingent" or "dependent," discovered through using the thesaurus and dictionary. I'm not thrilled with these choices, though, and wonder if anyone knows of a better one. The answer does not have to be colloquial.
Bonus: If there are better terms I could be using to describe "non-directional" and "directional" relationships, please share. This is my world now, and it would help to learn the formal lexicon.