Diversified Subgraph Query Generation with Group Fairness

This paper investigates the problem of subgraph query generation with output that satisfies both diversity and fairness constraints. Given a set of groups with associated cardinality requirements, it is to compute subgraph queries with diversified output that meanwhile covers the groups with the desired cardinality. Such need is evident in web and social search with fairness constraints. We formalize subgraph query generation as a bi-criteria optimization problem on the diversity and fairness properties of queries, and verify its hardness and approximability. We show that the problem is in Σp2 , and remains NP-complete even for single-node queries. Despite the hardness, (1) we show that approximations exist whenever a corresponding subset selection process provides good solutions, and provide feasible algorithms with performance guarantees for two practical query generation scenarios. We also present a fast heuristic algorithm for the general problem, which early terminates without enumerating queries. We experimentally verify that our algorithms can efficiently generate queries with desired diversity and coverage properties for targeted groups.