Large Language Models as Oracles for Ontology Alignment
Summary
Ontology alignment systems still struggle to produce highly reliable correspondences. Asking human experts to check doubtful mappings helps, but it becomes too costly for large ontologies. The authors test whether an LLM can take over that verification role. They extend the matcher LogMap so that only the mappings it flags as uncertain (M_ask) go to an LLM-based Oracle. The Oracle answers a True/False question built from ontology-driven prompts. These prompts vary in phrasing style, amount of surrounding context such as parent classes, and whether synonyms are included.
The evaluation covers nine tasks from the OAEI anatomy, largebio and bio-ml datasets. It compares 30 LLM–prompt combinations, measuring diagnostic quality with Sensitivity, Specificity and Youden's index. The full pipeline is compared with automatic LogMap and with simulated Oracles at varying error rates. LLM Oracles improve LogMap's alignments and placed second overall in the OAEI 2025 bio-ml track, though they remain clearly below a perfect Oracle. Because the LLM is queried only for hard cases, the approach keeps computational and financial costs modest.
Key points
- The LLM is invoked only for uncertain LogMap mappings. Prompt templates are built from three features: natural-language-friendly phrasing (NLF), extended context (EC) and synonyms (S).
- The experiments combine five LLMs (GPT-4o Mini and several Google Gemini Flash models) with six prompt templates. Open-weight Mistral, Llama and Qwen were additionally tested on anatomy.
- Benchmarks are nine OAEI matching tasks from the anatomy, largebio and bio-ml datasets.
- LogMap combined with an LLM Oracle (LogMapLLM) ranked top-2 overall in the OAEI 2025 bio-ml track.
- The code is released on GitHub (city-artificial-intelligence/logmap-llm, rai-ukraine-kga-llm) and Zenodo. The authors acknowledge several limitations:
- no study with human domain experts;
- possible training-data leakage;
- a focus on equivalence mappings only.
Topics Language models & pretraining Knowledge graphs & ontologies
Institutions
Cite
Cite as Sviatoslav Lushnei, Dmytro Shumskyi, Severyn Shykula, Ernesto Jiménez-Ruiz and Artur d'Avila Garcez. 2026. Large Language Models as Oracles for Ontology Alignment. Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers).
@inproceedings{lushnei2026large,
title = {{Large Language Models as Oracles for Ontology Alignment}},
author = {Sviatoslav Lushnei, Dmytro Shumskyi, Severyn Shykula, Ernesto Jiménez-Ruiz and Artur d'Avila Garcez},
booktitle = {Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)},
year = {2026},
doi = {10.18653/v1/2026.eacl-long.110},
url = {https://doi.org/10.18653/v1/2026.eacl-long.110}
}References
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