Despite the celebrated popularity of Graph Neural Networks (GNNs) across numerous applications, the ability of GNNs to generalize remains less explored. In this work, we propose to study the generalization of GNNs through a novel perspective - analyzing the entropy of graph homomorphism. By linking graph homomorphism with information-theoretic measures, we derive generalization bounds for both graph and node classifications. These bounds are capable of capturing subtleties inherent in various graph structures, including but not limited to paths, cycles and cliques. This enables a data-dependent generalization analysis with robust theoretical guarantees. To shed light on the generality of of our proposed bounds, we present a unifying framework that can characterize a broad spectrum of GNN models through the lens of graph homomorphism. We validate the practical applicability of our theoretical findings by showing the alignment between the proposed bounds and the empirically observed generalization gaps over both real-world and synthetic datasets.

通过分析图同态性的熵，我们提出了一种新的视角来研究图神经网络的泛化能力，并通过将图同态性与信息论度量联系起来，得出了适用于图和节点分类的泛化界限。通过我们提出的界限，能够捕捉到各种图结构的细微差别，包括但不限于路径、环和完全子图。通过图同态性，我们呈现了一个统一的框架，能够揭示广谱 GNN 模型的特性。通过在真实世界和人工合成数据集上观察到的泛化差距，我们验证了理论发现的实际可应用性。

基于同态性的图神经网络泛化