OLG++: A Semantic Extension of Obligation Logic Graph
This work addresses the problem of legal knowledge representation for municipal and interjurisdictional contexts, but appears incremental as it builds on prior graph-based models.
The authors tackled the problem of modeling regulatory and legal rules by developing OLG++, a semantic extension of the Obligation Logic Graph that introduces richer node and edge types for nuanced representations, and demonstrated its expressiveness through examples from food business regulations.
We present OLG++, a semantic extension of the Obligation Logic Graph (OLG) for modeling regulatory and legal rules in municipal and interjurisdictional contexts. OLG++ introduces richer node and edge types, including spatial, temporal, party group, defeasibility, and logical grouping constructs, enabling nuanced representations of legal obligations, exceptions, and hierarchies. The model supports structured reasoning over rules with contextual conditions, precedence, and complex triggers. We demonstrate its expressiveness through examples from food business regulations, showing how OLG++ supports legal question answering using property graph queries. OLG++ also improves over LegalRuleML by providing native support for subClassOf, spatial constraints, and reified exception structures. Our examples show that OLG++ is more expressive than prior graph-based models for legal knowledge representation.