p-Laplacian Based Graph Neural Networks
Guoji FuPeilin ZhaoYatao Bian
Develops a discrete regularization framework based on the -Laplacian to create graph neural networks that act as adaptive low-high-pass spectral filters, effectively handling heterophilic graphs and noisy topology where standard architectures fail.
Graph neural networks have become a leading approach for semi-supervised classification across complex systems, including social networks, biological interactomes, and molecular graphs. However, standard architectures rely heavily on the assumption of homophily—that connected nodes share identical or similar attributes and labels. In real-world environments with heterophily (where linked nodes possess different labels) or where graph structures contain noisy, misleading connections, traditional graph neural networks often experience severe performance degradation. In some instances, standard architectures perform substantially worse than simple multilayer perceptrons that ignore graph connectivity entirely.
The article develops and validates a generalized graph neural network framework, termed pGNN, based on discrete p-Laplacian regularization. The core objective is to formulate an adaptive message-passing mechanism capable of filtering information effectively across homophilic graphs, heterophilic networks, and topologies corrupted by noise.
To evaluate this framework, the authors conducted extensive transductive and inductive node classification experiments across 13 benchmark datasets (seven homophilic and six heterophilic networks), synthetic contextual stochastic block models with varying levels of homophily, and graphs with controlled rates of randomly injected edges (up to 100% random edges). The pGNN framework was systematically benchmarked against standard models, including multi-layer perceptrons, Graph Convolutional Networks, Graph Attention Networks, and generalized PageRank baselines.
The findings demonstrate substantial performance gains under challenging network conditions. First, on real-world heterophilic benchmarks, pGNN configurations significantly outperform conventional models; for example, on the Wisconsin dataset, pGNN achieves over 95% accuracy compared to approximately 62% for standard graph convolutional networks and 66% for graph attention networks. Second, on homophilic benchmarks, pGNN remains fully competitive with state-of-the-art architectures while outperforming baselines under limited supervision (e.g., 2.5% training splits). Third, in noise-stress evaluations with high edge-corruption rates, pGNN exhibits strong robustness, avoiding performance collapse and matching or exceeding independent node classification. Finally, theoretical and spectral analyses confirm that pGNN functions as an adaptive filter that dynamically concentrates aggregation weights to ignore non-informative edges.
These results demonstrate that organizations deploying machine learning on interconnected data do not need separate, specialized pipelines for homophilic and heterophilic topologies. The ability of pGNN to automatically prune misleading relationships reduces operational risks associated with noisy data and improves reliability in sparse-label environments.
Decision-makers should consider pGNN as a drop-in architectural replacement or plug-and-play enhancement for existing graph learning pipelines, particularly when graph quality is uncertain. When deploying the model, tuning the regularization parameter allows teams to balance reliance on graph structure versus raw node features. Before enterprise-scale implementation on massive networks, engineering teams should conduct pilot deployments and explore subgraph sampling methods to address the higher memory requirements typical of full-graph spectral methods.
- Paper: Semi-Supervised Classification with Graph Convolutional Networks, Thomas N. Kipf et al. (2017). Its foundational GCN formulation makes the neighbor-aggregation mechanism clear before pGNN replaces fixed propagation with a p-Laplacian-based adaptive rule.
- Paper: Convolutional Neural Networks on Graphs with Fast Localized Spectral Filtering, Michaël Defferrard et al. (2016). Its Laplacian-based spectral filtering provides the mathematical groundwork for understanding pGNN’s use of graph operators and frequency filtering.
- Paper: Beyond Homophily in Graph Neural Networks: Current Limitations and Effective Designs, Jiong Zhu et al. (2020). Its analysis of why conventional GNN designs fail under heterophily motivates the problem that pGNN’s adaptive aggregation addresses.
- Paper: Geom-GCN: Geometric Graph Convolutional Networks, Hongbin Pei et al. (2020). Its geometric aggregation approach shows how earlier GNNs addressed heterophily, giving context for pGNN’s distinct operator-based solution.
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