Rethinking Graph Generalization through the Lens of Sharpness-Aware Minimization
This work addresses the vulnerability of graph neural networks (GNNs) to minimal shift flipping (MSF)—a phenomenon where minor out-of-distribution perturbations induce misclassification under distributional shifts. From the perspective of Sharpness-Aware Minimization (SAM), the study establishes, for the first time, a theoretical connection between the local robustness radius and generalization error in graph learning, and proposes an energy-based function as a computable proxy for this radius. Building upon this insight, the authors introduce E2A, an energy-driven generative augmentation framework that leverages the energy landscape to guide the generation of pseudo out-of-distribution samples, thereby enhancing model robustness. Extensive experiments demonstrate that E2A significantly outperforms existing methods across multiple benchmarks, effectively mitigating the MSF issue and consistently improving the out-of-distribution generalization capability of GNNs.