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Main Authors: Chen, Ziang, Zhang, Qiao, Wang, Runzhong
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2502.03703
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author Chen, Ziang
Zhang, Qiao
Wang, Runzhong
author_facet Chen, Ziang
Zhang, Qiao
Wang, Runzhong
contents Graph neural networks (GNNs) have been widely used in graph-related contexts. It is known that the separation power of GNNs is equivalent to that of the Weisfeiler-Lehman (WL) test; hence, GNNs are imperfect at identifying all non-isomorphic graphs, which severely limits their expressive power. This work investigates $k$-hop subgraph GNNs that aggregate information from neighbors with distances up to $k$ and incorporate the subgraph structure. We prove that under appropriate assumptions, the $k$-hop subgraph GNNs can approximate any permutation-invariant/equivariant continuous function over graphs without cycles of length greater than $2k+1$ within any error tolerance. We also provide an extension to $k$-hop GNNs without incorporating the subgraph structure. Our numerical experiments on established benchmarks and novel architectures validate our theory on the relationship between the information aggregation distance and the cycle size.
format Preprint
id arxiv_https___arxiv_org_abs_2502_03703
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the Expressive Power of Subgraph Graph Neural Networks for Graphs with Bounded Cycles
Chen, Ziang
Zhang, Qiao
Wang, Runzhong
Machine Learning
Graph neural networks (GNNs) have been widely used in graph-related contexts. It is known that the separation power of GNNs is equivalent to that of the Weisfeiler-Lehman (WL) test; hence, GNNs are imperfect at identifying all non-isomorphic graphs, which severely limits their expressive power. This work investigates $k$-hop subgraph GNNs that aggregate information from neighbors with distances up to $k$ and incorporate the subgraph structure. We prove that under appropriate assumptions, the $k$-hop subgraph GNNs can approximate any permutation-invariant/equivariant continuous function over graphs without cycles of length greater than $2k+1$ within any error tolerance. We also provide an extension to $k$-hop GNNs without incorporating the subgraph structure. Our numerical experiments on established benchmarks and novel architectures validate our theory on the relationship between the information aggregation distance and the cycle size.
title On the Expressive Power of Subgraph Graph Neural Networks for Graphs with Bounded Cycles
topic Machine Learning
url https://arxiv.org/abs/2502.03703