Over-squashing in Spatiotemporal Graph Neural Networks

Fuente: arXiv
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Main Authors: Marisca, Ivan, Bamberger, Jacob, Alippi, Cesare, Bronstein, Michael M.
Format: Preprint
Published: 2025
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author Marisca, Ivan
Bamberger, Jacob
Alippi, Cesare
Bronstein, Michael M.
author_facet Marisca, Ivan
Bamberger, Jacob
Alippi, Cesare
Bronstein, Michael M.
contents Graph Neural Networks (GNNs) have achieved remarkable success across various domains. However, recent theoretical advances have identified fundamental limitations in their information propagation capabilities, such as over-squashing, where distant nodes fail to effectively exchange information. While extensively studied in static contexts, this issue remains unexplored in Spatiotemporal GNNs (STGNNs), which process sequences associated with graph nodes. Nonetheless, the temporal dimension amplifies this challenge by increasing the information that must be propagated. In this work, we formalize the spatiotemporal over-squashing problem and demonstrate its distinct characteristics compared to the static case. Our analysis reveals that, counterintuitively, convolutional STGNNs favor information propagation from points temporally distant rather than close in time. Moreover, we prove that architectures that follow either time-and-space or time-then-space processing paradigms are equally affected by this phenomenon, providing theoretical justification for computationally efficient implementations. We validate our findings on synthetic and real-world datasets, providing deeper insights into their operational dynamics and principled guidance for more effective designs.
format Preprint
id arxiv_https___arxiv_org_abs_2506_15507
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Over-squashing in Spatiotemporal Graph Neural Networks
Marisca, Ivan
Bamberger, Jacob
Alippi, Cesare
Bronstein, Michael M.
Machine Learning
Artificial Intelligence
Graph Neural Networks (GNNs) have achieved remarkable success across various domains. However, recent theoretical advances have identified fundamental limitations in their information propagation capabilities, such as over-squashing, where distant nodes fail to effectively exchange information. While extensively studied in static contexts, this issue remains unexplored in Spatiotemporal GNNs (STGNNs), which process sequences associated with graph nodes. Nonetheless, the temporal dimension amplifies this challenge by increasing the information that must be propagated. In this work, we formalize the spatiotemporal over-squashing problem and demonstrate its distinct characteristics compared to the static case. Our analysis reveals that, counterintuitively, convolutional STGNNs favor information propagation from points temporally distant rather than close in time. Moreover, we prove that architectures that follow either time-and-space or time-then-space processing paradigms are equally affected by this phenomenon, providing theoretical justification for computationally efficient implementations. We validate our findings on synthetic and real-world datasets, providing deeper insights into their operational dynamics and principled guidance for more effective designs.
title Over-squashing in Spatiotemporal Graph Neural Networks
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2506.15507