Neural Common Neighbor with Completion for Link Prediction
This work addresses link prediction for graph-based applications, offering a novel method that is incremental in combining structural features with MPNNs and handling incompleteness.
The authors tackled link prediction in graphs by proposing Neural Common Neighbor (NCN), which uses structural features to guide MPNN pooling, and enhanced it with Neural Common Neighbor with Completion (NCNC) to address graph incompleteness, achieving large-margin improvements over baselines and surpassing state-of-the-art models in benchmarks.
In this work, we propose a novel link prediction model and further boost it by studying graph incompleteness. First, we introduce MPNN-then-SF, an innovative architecture leveraging structural feature (SF) to guide MPNN's representation pooling, with its implementation, namely Neural Common Neighbor (NCN). NCN exhibits superior expressiveness and scalability compared with existing models, which can be classified into two categories: SF-then-MPNN, augmenting MPNN's input with SF, and SF-and-MPNN, decoupling SF and MPNN. Second, we investigate the impact of graph incompleteness -- the phenomenon that some links are unobserved in the input graph -- on SF, like the common neighbor. Through dataset visualization, we observe that incompleteness reduces common neighbors and induces distribution shifts, significantly affecting model performance. To address this issue, we propose to use a link prediction model to complete the common neighbor structure. Combining this method with NCN, we propose Neural Common Neighbor with Completion (NCNC). NCN and NCNC outperform recent strong baselines by large margins, and NCNC further surpasses state-of-the-art models in standard link prediction benchmarks. Our code is available at https://github.com/GraphPKU/NeuralCommonNeighbor.