Higher-Order GNNs Meet Efficiency: Sparse Sobolev Graph Neural Networks

TL;DR

This paper introduces S2-GNN, a sparse Sobolev GNN that efficiently captures higher-order relationships in graphs using spectral properties and Hadamard powers, offering robustness and competitive performance.

Contribution

We propose a novel sparse Sobolev GNN leveraging spectral similarities and Hadamard products to efficiently model higher-order graph relationships with robustness.

Findings

S2-GNN achieves competitive accuracy on node classification tasks.

The method maintains sparsity and reduces computational costs.

Theoretical analysis confirms robustness to graph perturbations.

Abstract

Graph Neural Networks (GNNs) have shown great promise in modeling relationships between nodes in a graph, but capturing higher-order relationships remains a challenge for large-scale networks. Previous studies have primarily attempted to utilize the information from higher-order neighbors in the graph, involving the incorporation of powers of the shift operator, such as the graph Laplacian or adjacency matrix. This approach comes with a trade-off in terms of increased computational and memory demands. Relying on graph spectral theory, we make a fundamental observation: the regular and the Hadamard power of the Laplacian matrix behave similarly in the spectrum. This observation has significant implications for capturing higher-order information in GNNs for various tasks such as node classification and semi-supervised learning. Consequently, we propose a novel graph convolutional operator based on the sparse Sobolev norm of graph signals. Our approach, known as Sparse Sobolev GNN (S2-GNN), employs Hadamard products between matrices to maintain the sparsity level in graph representations. S2-GNN utilizes a cascade of filters with increasing Hadamard powers to generate a diverse set of functions. We theoretically analyze the stability of S2-GNN to show the robustness of the model against possible graph perturbations. We also conduct a comprehensive evaluation of S2-GNN across various graph mining, semi-supervised node classification, and computer vision tasks. In particular use cases, our algorithm demonstrates competitive performance compared to state-of-the-art GNNs in terms of performance and running time.