Nodes and affiliations

In the game Six Degrees of Kevin Bacon, perhaps the most widely-known application of network science principles, the goal is to find a link between a given actor and the actor Kevin Bacon. For example, Jon Hamm can be connected to Kevin Bacon as follows: Jon Hamm was in Bridesmaids with Rose Byrne, who was in X-Men: First Class, with Kevin Bacon. This game takes place on a network. In one version of the network, nodes represent actors and edges represent movies that two actors both appeared in. This version of the network (let's call it the actor-actor network) is sufficient for finding Kevin Bacon, but it doesn't fully represent the relationships between actors and movies. Movies typically have a cast of many actors, but each edge in the actor-actor network only corresponds to two actors. Consequently, there need to be many edges for each movie...