Legal Knowledge Graph Foundations, Part I: URI-Addressable Abstract Works (LRMoo F1 to schema.org)

TL;DR

This paper develops a formal, web-compatible model for legal norms, mapping the foundational abstract legal Work to schema.org, enabling interoperable, machine-readable legal knowledge graphs with stable URIs.

Contribution

It introduces a detailed mapping of the LRMoo F1 legal Work to schema.org, establishing a URI-addressable, interoperable foundation for legal knowledge graphs on the Semantic Web.

Findings

Created a JSON-LD mapping for legal norms

Demonstrated stable URIs for Brazilian legislation

Laid groundwork for deterministic legal knowledge graphs

Abstract

Building upon a formal, event-centric model for the diachronic evolution of legal norms grounded in the IFLA Library Reference Model (LRMoo), this paper addresses the essential first step of publishing this model's foundational entity-the abstract legal Work (F1)-on the Semantic Web. We propose a detailed, property-by-property mapping of the LRMoo F1 Work to the widely adopted schema.org/Legislation vocabulary. Using Brazilian federal legislation from the Normas.leg.br portal as a practical case study, we demonstrate how to create interoperable, machine-readable descriptions via JSON-LD, focusing on stable URN identifiers, core metadata, and norm relationships. This structured mapping establishes a stable, URI-addressable anchor for each legal norm, creating a verifiable "ground truth". It provides the essential, interoperable foundation upon which subsequent layers of the model, such as temporal versions (Expressions) and internal components, can be built. By bridging formal ontology with web-native standards, this work paves the way for building deterministic and reliable Legal Knowledge Graphs (LKGs), overcoming the limitations of purely probabilistic models.