How Particle System Theory Enhances Hypergraph Message Passing
Yixuan Ma, Kai Yi, Pietro Lio, Shi Jin, Yu Guang Wang
TL;DR
This paper addresses over-smoothing and heterophily in hypergraph neural networks by recasting hypergraph message passing as interacting-particle dynamics. It introduces Hypergraph Atomic Message Passing (HAMP) with two instantiations, HAMP-I (first-order) and HAMP-II (second-order), incorporating attractive and repulsive forces, Allen-Cahn damping, and optional Brownian noise to enable deep, stable propagation. The authors prove a positive lower bound on the hypergraph Dirichlet energy and establish L2-type separability results, ensuring anti-over-smoothing behavior, while empirical results on nine real-world hypergraph benchmarks demonstrate competitive performance, particularly on heterophilic data. The framework unifies diffusion perspectives with particle dynamics, offering a physically interpretable, scalable approach to modeling high-order interactions and uncertainty in complex systems, with potential for broader applications in biology and beyond.
Abstract
Hypergraphs effectively model higher-order relationships in natural phenomena, capturing complex interactions beyond pairwise connections. We introduce a novel hypergraph message passing framework inspired by interacting particle systems, where hyperedges act as fields inducing shared node dynamics. By incorporating attraction, repulsion, and Allen-Cahn forcing terms, particles of varying classes and features achieve class-dependent equilibrium, enabling separability through the particle-driven message passing. We investigate both first-order and second-order particle system equations for modeling these dynamics, which mitigate over-smoothing and heterophily thus can capture complete interactions. The more stable second-order system permits deeper message passing. Furthermore, we enhance deterministic message passing with stochastic element to account for interaction uncertainties. We prove theoretically that our approach mitigates over-smoothing by maintaining a positive lower bound on the hypergraph Dirichlet energy during propagation and thus to enable hypergraph message passing to go deep. Empirically, our models demonstrate competitive performance on diverse real-world hypergraph node classification tasks, excelling on both homophilic and heterophilic datasets.
