2.17. Finding Intersections of Paths

To ask Cassie which elephants can fly, we want her to find all nodes that represent elephants and that represent things that can fly. I.e., we want her to find all nodes that have a (member- class) path to elephant and an (object- ability) path to fly. This is the intersection of the two sets of nodes she found for us before. To say this,

evaluate:

(find (member- class) elephant (object- ability) fly)