HGCL: Hierarchical Graph Contrastive Learning for User-Item Recommendation

Fuente: arXiv
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Main Authors: Xue, Jiawei, Yang, Zhen, Lin, Haitao, Zhang, Ziji, Wang, Luzhu, Gu, Yikun, Xu, Yao, Li, Xin
Format: Preprint
Published: 2025
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author Xue, Jiawei
Yang, Zhen
Lin, Haitao
Zhang, Ziji
Wang, Luzhu
Gu, Yikun
Xu, Yao
Li, Xin
author_facet Xue, Jiawei
Yang, Zhen
Lin, Haitao
Zhang, Ziji
Wang, Luzhu
Gu, Yikun
Xu, Yao
Li, Xin
contents Graph Contrastive Learning (GCL), which fuses graph neural networks with contrastive learning, has evolved as a pivotal tool in user-item recommendations. While promising, existing GCL methods often lack explicit modeling of hierarchical item structures, which represent item similarities across varying resolutions. Such hierarchical item structures are ubiquitous in various items (e.g., online products and local businesses), and reflect their inherent organizational properties that serve as critical signals for enhancing recommendation accuracy. In this paper, we propose Hierarchical Graph Contrastive Learning (HGCL), a novel GCL method that incorporates hierarchical item structures for user-item recommendations. First, HGCL pre-trains a GCL module using cross-layer contrastive learning to obtain user and item representations. Second, HGCL employs a representation compression and clustering method to construct a two-hierarchy user-item bipartite graph. Ultimately, HGCL fine-tunes user and item representations by learning on the hierarchical graph, and then provides recommendations based on user-item interaction scores. Experiments on three widely adopted benchmark datasets ranging from 70K to 382K nodes confirm the superior performance of HGCL over existing baseline models, highlighting the contribution of hierarchical item structures in enhancing GCL methods for recommendation tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2505_19020
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle HGCL: Hierarchical Graph Contrastive Learning for User-Item Recommendation
Xue, Jiawei
Yang, Zhen
Lin, Haitao
Zhang, Ziji
Wang, Luzhu
Gu, Yikun
Xu, Yao
Li, Xin
Information Retrieval
Artificial Intelligence
Graph Contrastive Learning (GCL), which fuses graph neural networks with contrastive learning, has evolved as a pivotal tool in user-item recommendations. While promising, existing GCL methods often lack explicit modeling of hierarchical item structures, which represent item similarities across varying resolutions. Such hierarchical item structures are ubiquitous in various items (e.g., online products and local businesses), and reflect their inherent organizational properties that serve as critical signals for enhancing recommendation accuracy. In this paper, we propose Hierarchical Graph Contrastive Learning (HGCL), a novel GCL method that incorporates hierarchical item structures for user-item recommendations. First, HGCL pre-trains a GCL module using cross-layer contrastive learning to obtain user and item representations. Second, HGCL employs a representation compression and clustering method to construct a two-hierarchy user-item bipartite graph. Ultimately, HGCL fine-tunes user and item representations by learning on the hierarchical graph, and then provides recommendations based on user-item interaction scores. Experiments on three widely adopted benchmark datasets ranging from 70K to 382K nodes confirm the superior performance of HGCL over existing baseline models, highlighting the contribution of hierarchical item structures in enhancing GCL methods for recommendation tasks.
title HGCL: Hierarchical Graph Contrastive Learning for User-Item Recommendation
topic Information Retrieval
Artificial Intelligence
url https://arxiv.org/abs/2505.19020