Indexing Public-Private Graphs
Aaron F. Archer, Silvio Lattanzi, Peter Likarish, Sergei Vassilvitskii · 2017
We consider the reachability indexing problem for private-public directed graphs. In these graphs nodes come in three flavors: public--nodes visible to all users, private--nodes visible to a specific set of users, and protected--nodes visible to any user who can see at least one of the node's parents. We are interested in computing the set of nodes visible to a specific user online. There are two obvious algorithms: precompute the result for every user, or run a reachability algorithm at query time. This paper explores the trade-off between these two strategies.