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Main Authors: Tang, Yinxu, Huang, Chengsong, Huang, Jiaxin, Yeoh, William
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2512.17043
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author Tang, Yinxu
Huang, Chengsong
Huang, Jiaxin
Yeoh, William
author_facet Tang, Yinxu
Huang, Chengsong
Huang, Jiaxin
Yeoh, William
contents Knowledge Graph Question Answering (KGQA) has largely focused on entity-centric queries that return a single answer entity. However, many real-world questions are inherently relational, aiming to understand how entities are associated rather than which entity satisfies a query. In this work, we introduce relation-centric KGQA, a complementary setting in which the answer is a subgraph that represents the semantic relations among entities. The main challenge lies in the abundance of candidate subgraphs, where trivial or overly common connections often obscure the identification of unique and informative answers. To tackle this, we propose UniRel, a unified modular framework that combines a subgraph retriever with an LLM fine-tuned using reinforcement learning. The framework uses a reward function to prefer compact and specific subgraphs with informative relations and low-degree intermediate entities. Experiments show that UniRel improves connectivity and reward over Prompting baselines and generalizes well to unseen entities and relations. Moreover, UniRel can be applied to conventional entity-centric KGQA, achieving competitive or improved performance in several settings.
format Preprint
id arxiv_https___arxiv_org_abs_2512_17043
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle UniRel: Relation-Centric Knowledge Graph Question Answering with RL-Tuned LLM Reasoning
Tang, Yinxu
Huang, Chengsong
Huang, Jiaxin
Yeoh, William
Artificial Intelligence
Knowledge Graph Question Answering (KGQA) has largely focused on entity-centric queries that return a single answer entity. However, many real-world questions are inherently relational, aiming to understand how entities are associated rather than which entity satisfies a query. In this work, we introduce relation-centric KGQA, a complementary setting in which the answer is a subgraph that represents the semantic relations among entities. The main challenge lies in the abundance of candidate subgraphs, where trivial or overly common connections often obscure the identification of unique and informative answers. To tackle this, we propose UniRel, a unified modular framework that combines a subgraph retriever with an LLM fine-tuned using reinforcement learning. The framework uses a reward function to prefer compact and specific subgraphs with informative relations and low-degree intermediate entities. Experiments show that UniRel improves connectivity and reward over Prompting baselines and generalizes well to unseen entities and relations. Moreover, UniRel can be applied to conventional entity-centric KGQA, achieving competitive or improved performance in several settings.
title UniRel: Relation-Centric Knowledge Graph Question Answering with RL-Tuned LLM Reasoning
topic Artificial Intelligence
url https://arxiv.org/abs/2512.17043