Case-to-Statute Retrieval—identifying applicable statutes from case facts—is essential for judicial efficiency but remains underexplored in low-resource languages like Vietnamese, where annotated legal corpora are scarce and domain-specific challenges persist. To advance research in this setting, we introduce ViCSR, a new benchmark of 10,000 Vietnamese criminal judgments and 1,122 statutory articles with citation-based relevance labels. We further propose a lightweight two-stage framework that performs efficient candidate retrieval with a fine-tuned Vietnamese bi-encoder and leverages citation structure for reranking with a compact heterogeneous GNN. Experiments show clear improvements over strong sparse and dense baselines, highlighting the importance of both domain adaptation and structure-aware modeling in low-resource legal IR. We will publicly release the benchmark, code, and checkpoints.

International audience

In the legal field, accurately interpreting and applying legal definitions is crucial yet challenging due to inherent ambiguities. This paper introduces DeCoRA, a novel framework that enhances legal argumentation by incorporating context-based reasoning to address these ambiguities, with a focus on the judge as the central decision maker. Unlike black-box models, such as generative models or outcome prediction systems, which often produce outputs without fully explaining the reasoning behind their conclusions, DeCoRA emphasizes transparency by modeling the judicial decision-making process in a structured and interpretable manner. Our key contributions include: (1) a tree-based knowledge base that organizes legal definitions, highlighting their relationships and effects; (2) a context-aware definition framework enabling judges to interpret definitions considering legal and contextual relevance; and (3) an effective method for handling complex legal scenarios with conflicting or overlapping definitions.