RATIO: A Graph-Aware Framework for Precedent-Grounded Legal Retrieval

A graph-aware retrieval framework for legal precedent search that explicitly models the citation network of Nigerian case law rather than relying solely on semantic similarity. Includes the first open citation graph for Nigerian case law (14,437 judgments, 51,465 typed citation edges), a binding horizon filter operationalising temporal validity and jurisdictional binding as executable graph masks, and a trained Graph Attention Network for authority-aware retrieval re-ranking.