On the Trade-off between Over-smoothing and Over-squashing in Deep Graph Neural Networks

Autor: Giraldo, Jhony H., Skianis, Konstantinos, Bouwmans, Thierry, Malliaros, Fragkiskos D.
Rok vydání: 2022
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1145/3583780.3614997
Popis: Graph Neural Networks (GNNs) have succeeded in various computer science applications, yet deep GNNs underperform their shallow counterparts despite deep learning's success in other domains. Over-smoothing and over-squashing are key challenges when stacking graph convolutional layers, hindering deep representation learning and information propagation from distant nodes. Our work reveals that over-smoothing and over-squashing are intrinsically related to the spectral gap of the graph Laplacian, resulting in an inevitable trade-off between these two issues, as they cannot be alleviated simultaneously. To achieve a suitable compromise, we propose adding and removing edges as a viable approach. We introduce the Stochastic Jost and Liu Curvature Rewiring (SJLR) algorithm, which is computationally efficient and preserves fundamental properties compared to previous curvature-based methods. Unlike existing approaches, SJLR performs edge addition and removal during GNN training while maintaining the graph unchanged during testing. Comprehensive comparisons demonstrate SJLR's competitive performance in addressing over-smoothing and over-squashing.
Comment: This paper has been accepted for publication at the 32nd ACM International Conference on Information and Knowledge Management (CIKM) 2023
Databáze: arXiv