Logic-infused knowledge graph QA: Enhancing large language models for specialized domains through Prolog integration

Abstract

Efficiently answering questions over complex, domain-specific knowledge graphs remain a substantial challenge, as large language models (LLMs) often lack the logical reasoning abilities and particular knowledge required for such tasks. This paper presents a novel framework integrating LLMs with logical programming languages like Prolog for Logic-Infused Knowledge Graph Question Answering (KGQA) in specialized domains. The proposed methodology uses a transformer-based encoder–decoder architecture. An encoder reads the question, and a named entity recognition (NER) module connects entities to the knowledge graph. The extracted entities are fed into a grammar-guided decoder, producing a logical form (Prolog query) that captures the semantic constraints and relationships. The Prolog query is executed over the knowledge graph to perform symbolic reasoning and retrieve relevant answer entities. Comprehensive experiments on the MetaQA benchmark dataset demonstrate the superior performance of this logic-infused method in accurately identifying correct answer entities from the knowledge graph. Even when trained on a limited subset of annotated data, it outperforms state-of-the-art baselines, achieving 89.60 % and F1-scores of up to 89.61 %, showcasing its effectiveness in enhancing large language models with symbolic reasoning capabilities for specialized question-answering tasks. The seamless integration of LLMs and logical programming enables the proposed framework to reason effectively over complex, domain-specific knowledge graphs, overcoming a key limitation of existing KGQA systems. In specialized domains, the interpretability provided by representing questions such as Prologue queries is a valuable asset.