Continuous graph neural models based on differential equations have expanded the architecture of graph neural networks (GNNs). Due to the connection between graph diffusion and message passing, diffusion-based models have been widely studied. However, diffusion naturally drives the system towards an equilibrium state, leading to issues like over-smoothing. To this end, we propose GRADE inspired by graph aggregation-diffusion equations, which includes the delicate balance between nonlinear diffusion and aggregation induced by interaction potentials. The node representations obtained through aggregation-diffusion equations exhibit metastability, indicating that features can aggregate into multiple clusters. In addition, the dynamics within these clusters can persist for long time periods, offering the potential to alleviate over-smoothing effects. This nonlinear diffusion in our model generalizes existing diffusion-based models and establishes a connection with classical GNNs. We prove that GRADE achieves competitive performance across various benchmarks and alleviates the over-smoothing issue in GNNs evidenced by the enhanced Dirichlet energy.

基于微分方程的连续图神经模型拓展了图神经网络的架构，通过聚合-扩散方程启发的GRADE模型在非线性扩散和聚合之间找到了一种微妙的平衡，通过产生亚稳态节点表示聚集成多个聚类，从而缓解了过度平滑的问题，该模型达到了竞争性的性能，证明了其在图神经网络中减轻过度平滑问题的作用。

图神经聚合-扩散与亚稳态