Mixture of Structural-and-Textual Retrieval over Text-rich Graph Knowledge Bases

ACL ARR 2025 February Submission5179 Authors

Abstract: Text-rich Graph Knowledge Bases (TG-KBs) have become increasingly crucial for answering queries by providing textual and structural knowledge. However, current retrieval methods often retrieve these two types of knowledge in isolation without considering their mutual reinforcement and existing hybrid methods even bypass structural retrieval entirely. To fill this gap, we propose a Mixture of Structural-and-Textual Retrieval (MoR) to retrieve these two types of knowledge via a Planning-Reasoning-Organizing framework. In the Planning stage, MoR generates textual planning graphs delineating the logic for answering queries. Following planning graphs, in the Reasoning stage, MoR interweaves structural traversal and textual matching to obtain candidates from TG-KBs. In the Organizing stage, MoR further reranks fetched candidates based on their structural trajectory. Extensive experiments demonstrate the superiority of MoR in harmonizing structural and textual retrieval with inspiring insights, including imbalanced retrieving performance across different query logics and the benefits of integrating structural trajectories for candidate reranking.

Paper Type: Long

Research Area: Information Retrieval and Text Mining

Research Area Keywords: Graph Retrieval-augmented generation, Text-rich graph knowledge bases, Mixture of experts

Contribution Types: NLP engineering experiment

Languages Studied: English

Submission Number: 5179