End-to-End Graph Retrieval Pipeline for Specialized Domains

Haraldur Davidsson, Hazar Harmouch


Abstract
We present an end-to-end pipeline for constructing a domain-specific knowledge graph from instructional text using Large Language Model assisted extraction. Applied to the Icelandic Riding Levels, a 602 pages training corpus for riders of the Icelandic Horse, the pipeline produces a hyper-relational knowledge graph of 9,382 nodes and 16,423 edges, where schema-constrained qualifiers preserve the conditional and procedural context that standard triples discard. To evaluate the resulting graph, we introduce the first expert validated question answering benchmark for this domain: 252 questions across four reasoning categories. Comparing Graph-, Text-, and Hybrid-retrieval augmented generation methods, we find that Text-based achieves the highest overall accuracy, but that Graph-based provides the only correct answer for a subset of queries, particularly where the corpus contains competing values for the same fact. A failure analysis traces the majority of Graph-based retrieval errors to context dilution at high-degree hub nodes, an algorithmic limitation in graph traversal. We discuss implications for adaptive retrieval strategies that route queries to the appropriate modality.
Anthology ID:
2026.kallm-1.16
Volume:
Proceedings of the Knowledge Graphs and Large Language Models Workshop (KG-LLM) @ LREC26
Month:
May
Year:
2026
Address:
Palma, Mallorca (Spain)
Editors:
Gilles Sérasset, Katerina Gkirtzou, Michael Cochez, Jan-Christoph Kalo
Venues:
KaLLM | WS
SIG:
Publisher:
ELRA Language Resources Association (ELRA)
Note:
Pages:
155–165
Language:
External URL:
https://lrec.elra.info/lrec2026-ws-kgllm-16
DOI:
10.63317/3xjhui2zyiws
Bibkey:
Cite (ACL):
Haraldur Davidsson and Hazar Harmouch. 2026. End-to-End Graph Retrieval Pipeline for Specialized Domains. In Proceedings of the Knowledge Graphs and Large Language Models Workshop (KG-LLM) @ LREC26, pages 155–165, Palma, Mallorca (Spain). ELRA Language Resources Association (ELRA).
Cite (Informal):
End-to-End Graph Retrieval Pipeline for Specialized Domains (Davidsson & Harmouch, KaLLM 2026)
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