Automatic Construction of a Legal Citation Graph from 100 Million Ukrainian Court Decisions: Large-Scale Extraction, Topological Analysis, and Ontology-Driven Clustering
Quick Take
A legal citation graph from 100 million Ukrainian court decisions reveals insights into judicial structure and legislative dynamics.
Key Points
- Extracted 502 million citation links from 100.7 million decisions.
- Identified legal domain boundaries using Louvain community detection.
- Citation features predict legislative importance with high accuracy.
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~2 min readAbstract:Half a billion citation edges extracted from 100.7 million Ukrainian court decisions reveal that judicial citation structure encodes legal domain boundaries without supervision and predicts future legislative importance with near-perfect accuracy. We construct the first large-scale citation graph from the complete EDRSR registry (99.5 million full texts, 1.1 TB), extracting 502 million citation links across six types via regex on commodity hardware in approximately 5 hours, with precision of 1.00 on a 200-decision validation sample (95% Wilson CI: [0.982, 1.000]).
Three principal findings emerge. (1) The degree distribution follows a power law (alpha = 1.57 +/- 0.008), placing the Ukrainian court network near the EU Court of Justice and below the US Supreme Court, with hub articles cited by millions of decisions. (2) Louvain community detection on the co-citation projection recovers legal domain boundaries (civil, criminal, administrative, commercial) with modularity Q = 0.44-0.55 and temporal stability (NMI = 0.83-0.86 across periods), constituting an automatically constructed legal ontology grounded in judicial practice. (3) Citation features predict top-1000 articles with AUC = 0.9984, substantially outperforming a naive frequency baseline (P@1000 = 0.655); temporal dynamics detect legislative regime changes as phase transitions and the 2022 invasion as a citation entropy spike (H: 11.02 -> 13.49) with emergent wartime legislation nodes.
The citation-derived ontology is operationalized as the domain layer of a workflow memory system for LLM-assisted legal analysis, connecting to the ontology-controlled paradigm. The extraction pipeline, analysis code, and aggregated statistics are released as open data.
| Comments: | 15 pages, 7 figures, 2 tables, 21 references |
| Subjects: | Computation and Language (cs.CL); Digital Libraries (cs.DL); Information Retrieval (cs.IR) |
| Cite as: | arXiv:2605.15362 [cs.CL] |
| (or arXiv:2605.15362v1 [cs.CL] for this version) | |
| https://doi.org/10.48550/arXiv.2605.15362 arXiv-issued DOI via DataCite (pending registration) |
Submission history
From: Volodymyr Ovcharov [view email]
[v1]
Thu, 14 May 2026 19:42:20 UTC (26 KB)
— Originally published at arxiv.org
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