Densest Multipartite Subgraph Search in Heterogeneous Information Networks

Cohesive multipartite subgraphs (CMS) in heterogeneous information networks (HINs) uncover closely connected vertex groups of multiple types, enhancing real applications like community search and anomaly detection. However, existing works for HINs pay less attention to searching CMS. In this paper, we leverage wellestablished concepts of meta-path and densest subgraph to propose a novel CMS model called the densest P-partite subgraph. Given a multipartite subgraph of an HIN induced by 𝑖=| P | types of vertices defined in a query meta-path P (i.e., a P-partite subgraph), we devise a novel density function which is the number of the instances of P over the geometric mean of the sizes of 𝑖 different types of vertex sets in the subgraph. A P-partite subgraph with the highest density serves as the optimum result. To find the densest P-partite subgraph in an HIN with 𝑛 vertices, we first design an exact algorithm with a runtime cost equivalent to solving Θ( |M| ) instances of the min-cut problem where |M|=O ( ( 𝑛 𝑖 ) 𝑖 ). Then, we attempt a more efficient approximation algorithm that achieves a ratio of 1 𝑖 but still incurs the cost of solving Θ( |M| ) instances of our proposed peeling problem. Both approaches struggle with scalability due to Θ( |M| ). To overcome this bottleneck, we improve the exact algorithm with novel pruning rules that non-trivially reduce the number of min-cut problem instances to solve to O ( |M| ). Empirically, 70-90% instances are pruned, making the improved exact algorithm significantly faster than the approximation algorithm. Extensive experiments on real datasets demonstrate the effectiveness of the proposed model and the efficiency of our algorithms.