Extraction of Legal Term Definitions from German Statutory Texts and Court Decisions

Abstract

In order to be able to apply the regulations of our laws to actual cases, legal practitioners must work on the basis of clear interpretations of the terms contained therein. For this interpretation - among other criteria - existing definitions of terms have an important role to play. Firstly, the legislator deliberately controls the leeway for interpretation of the terms in the statutory text through included definitions, and secondly, ongoing jurisdiction also constitutes a source of definitory information. However, this information, which is essential for understanding the legal texts, is not provided in a structured format optimized for efficient research.

To solve this problem, this thesis presents a system that allows contextualized research for legal term definitions in German statutory texts and court decisions. For this purpose, in a first step the necessary theoretical framework for the classification of definitory statements with regard to their function and textual realization is created. On this basis, both rule-based and BERT-model-based extraction and classification procedures for definitions from German statutory texts and court decisions are presented and integrated into a coherent system. Part of this system, in addition to definition extraction, is the assignment of elaborating statements to core definitions and a check of the extracted definition candidates concerning their validity for a certain text passage.