This paper studies Large Language Models (LLMs) for structured data--particularly graphs--a crucial data modality that remains underexplored in the LLM literature. We aim to understand when and why the incorporation of structural information inherent in graph data can improve the prediction performance of LLMs on node classification tasks. To address the ``when'' question, we examine a variety of prompting methods for encoding structural information, in settings where textual node features are either rich or scarce. For the ``why'' questions, we probe into two potential contributing factors to the LLM performance: data leakage and homophily. Our exploration of these questions reveals that (i) LLMs can benefit from structural information, especially when textual node features are scarce; (ii) there is no substantial evidence indicating that the performance of LLMs is significantly attributed to data leakage; and (iii) the performance of LLMs on a target node is strongly positively related to the local homophily ratio of the node.

该研究探讨了大型语言模型（LLMs）在结构化数据（尤其是图形）上的应用，旨在理解何时以及为何将图形数据中固有的结构信息纳入到LLMs的节点分类任务中可以提高预测性能。

LLM是否能够有效利用结构信息进行图学习：何时以及为什么