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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.

How Particle System Theory Enhances Hypergraph Message Passing

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.

Paper Structure

This paper contains 45 sections, 9 theorems, 58 equations, 5 figures, 9 tables, 2 algorithms.

Key Result

Proposition 5.2

For Eq. eq:1st order, suppose the above assumptions are satisfied. Define the mean value $\mathbf{\Bar{x}} := \frac{1}{N}\sum\limits_{i=1}^N \mathbf{x}_i$, and the second moments $M_2(\mathbf{x}):= \sum \limits_{i=1}^N \mathbf{x}_i^2.$ Then for sufficiently large $N_1,N_2$, there exist constants $\l with a positive constant $\mu$, where $\widehat{M}_2(t):=M_2(\mathbf{x}^{(1)}(t))+M_2(\mathbf{x}^{(

Figures (5)

  • Figure 1: An illustration for HAMP framework. The property $\mathbf{p}$ can account for feature or velocity.
  • Figure 2: An empirical analysis of the depth-accuracy correlation in deep neural networks. The shaded area represents the standard deviation, helping to show the range of accuracy fluctuations.
  • Figure 3: Significance plot for noise on Senate dataset.
  • Figure 4: The t-SNE visualization of vertex representation evolution of HAMP-I (the first row) and HAMP-II (the second row) on Congress dataset. The colors represent the class labels.
  • Figure 5: Time-Memory tradeoff analysis of different methods on Walmart dataset. SD denotes the standard deviation of time consumption.

Theorems & Definitions (13)

  • Definition 5.1
  • Proposition 5.2: $L_2$ separation of HAMP-I
  • Proposition 5.3: $L_2$ separation of HAMP-II, fang2019emergent
  • Proposition 5.4: Lower bound of the Dirichlet energy
  • Lemma B.1: $L_2$ estimate for $M_2$
  • Proposition B.2
  • Lemma B.3
  • Lemma B.4
  • Proposition B.5: $L_2$ separation of HAMP-I
  • Remark B.6
  • ...and 3 more