FiDeLiS: Faithful Reasoning in Large Language Models for Knowledge Graph Question Answering

Yuan Sui, Yufei He, Nian Liu, Xiaoxin He, Kun Wang, Bryan Hooi


Abstract
Large Language Models (LLMs) are often challenged by generating erroneous or hallucinated responses, especially in complex reasoning tasks. Leveraging Knowledge Graphs (KGs) as external knowledge sources has emerged as a viable solution. However, existing KG-enhanced methods, either retrieval-based or agent-based, encounter difficulties in accurately retrieving knowledge and efficiently traversing KGs at scale. In this paper, we propose a unified framework, FiDeLiS, designed to improve the factuality of LLM responses by anchoring answers to verifiable reasoning steps retrieved from KGs. To achieve this, we leverage step-wise beam search with a deductive scoring function, allowing the LLM to validate reasoning process step by step, and halt the search once the question is deducible. In addition, we propose a Path-RAG module to pre-select a smaller candidate set for each beam search step, reducing computational costs by narrowing the search space. Extensive experiments show that our method, as a training-free framework, not only improve the performance but also enhance the factuality and interpretability across different benchmarks.
Anthology ID:
2025.findings-acl.436
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
8315–8330
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URL:
https://preview.aclanthology.org/landing_page/2025.findings-acl.436/
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Cite (ACL):
Yuan Sui, Yufei He, Nian Liu, Xiaoxin He, Kun Wang, and Bryan Hooi. 2025. FiDeLiS: Faithful Reasoning in Large Language Models for Knowledge Graph Question Answering. In Findings of the Association for Computational Linguistics: ACL 2025, pages 8315–8330, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
FiDeLiS: Faithful Reasoning in Large Language Models for Knowledge Graph Question Answering (Sui et al., Findings 2025)
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https://preview.aclanthology.org/landing_page/2025.findings-acl.436.pdf