On the Relationship Between Robustness and Expressivity of Graph Neural Networks

Fuente: arXiv
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Autori principali: Kummer, Lorenz, Gansterer, Wilfried N., Kriege, Nils M.
Natura: Preprint
Pubblicazione: 2025
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author Kummer, Lorenz
Gansterer, Wilfried N.
Kriege, Nils M.
author_facet Kummer, Lorenz
Gansterer, Wilfried N.
Kriege, Nils M.
contents We investigate the vulnerability of Graph Neural Networks (GNNs) to bit-flip attacks (BFAs) by introducing an analytical framework to study the influence of architectural features, graph properties, and their interaction. The expressivity of GNNs refers to their ability to distinguish non-isomorphic graphs and depends on the encoding of node neighborhoods. We examine the vulnerability of neural multiset functions commonly used for this purpose and establish formal criteria to characterize a GNN's susceptibility to losing expressivity due to BFAs. This enables an analysis of the impact of homophily, graph structural variety, feature encoding, and activation functions on GNN robustness. We derive theoretical bounds for the number of bit flips required to degrade GNN expressivity on a dataset, identifying ReLU-activated GNNs operating on highly homophilous graphs with low-dimensional or one-hot encoded features as particularly susceptible. Empirical results using ten real-world datasets confirm the statistical significance of our key theoretical insights and offer actionable results to mitigate BFA risks in expressivity-critical applications.
format Preprint
id arxiv_https___arxiv_org_abs_2504_13786
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the Relationship Between Robustness and Expressivity of Graph Neural Networks
Kummer, Lorenz
Gansterer, Wilfried N.
Kriege, Nils M.
Machine Learning
We investigate the vulnerability of Graph Neural Networks (GNNs) to bit-flip attacks (BFAs) by introducing an analytical framework to study the influence of architectural features, graph properties, and their interaction. The expressivity of GNNs refers to their ability to distinguish non-isomorphic graphs and depends on the encoding of node neighborhoods. We examine the vulnerability of neural multiset functions commonly used for this purpose and establish formal criteria to characterize a GNN's susceptibility to losing expressivity due to BFAs. This enables an analysis of the impact of homophily, graph structural variety, feature encoding, and activation functions on GNN robustness. We derive theoretical bounds for the number of bit flips required to degrade GNN expressivity on a dataset, identifying ReLU-activated GNNs operating on highly homophilous graphs with low-dimensional or one-hot encoded features as particularly susceptible. Empirical results using ten real-world datasets confirm the statistical significance of our key theoretical insights and offer actionable results to mitigate BFA risks in expressivity-critical applications.
title On the Relationship Between Robustness and Expressivity of Graph Neural Networks
topic Machine Learning
url https://arxiv.org/abs/2504.13786