XML standard for the markup of legal sources
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This page lists a number of examples to illustrate the use of MetaLex for different kinds and versions of documents in the spirit of the MetaLex Guidelines. The examples make extensive use of the XSL Stylesheets which are part of the MetaLex distribution. These stylesheets are dynamically applied to the source documents using an Apache Cocoon server. The MetaLex zip file layout is a direct copy of the contents of the dynamic part of this website. The examples show how to use multiple language versions of the same regulation, how to generate RDF (or more specifically OWL Description Logic) from MetaLex XML documents, and how tolocalize the MetaLex schema.

These examples are all `live’. If you wish to apply XSL Stylesheets offline, for testing your own MetaLex XML documents, or for exploring the distribution, you can either download Apache Xalan-Java 2.7.0 and use the command-line tools provided in the `tools’ directory of the distribution, or you can download the convenient MetalexStylertool.

Advanced Metadata in E-Government

RDF, like XML is an open standard from the World Wide Web Consortium (W3C) that is well-supported with free software. In RDF, statements are encoded as as (subject, predicate, object) triples. The RDF data model is based on the concept of astatement and the concept of `quotation‘ (or reification) of statements. An example of the use of RDF to define metadata is the Dublin Core initiative.

Quotation can be used to make statements about (reified) statements — the statement is treated as the subject or object of another statement. Quotation allows one to create trust, because it allows one to express where something was stated, who stated it, who modeled a statement made by someone, and what level of guarantee they dare to associate with it. `Syndication’ of information is based on this notion of trust. You may be willing to pay for advice, for instance, if you trust the party that gives it even if advice on the same subject is also available for free from other parties.

RDF Schema and OWL

In addition to the RDF data model, additional RDF Schema and Web Ontology Language (OWL) statements can be defined. Both RDF Schema and OWL include the RDF model, but pose restrictions to it which make it useful for defining and describing statements in terms of classes and restrictions on properties, and allow the use of reasoners (e.g. FACT++, Racer, Pellet, …) to perform standard inferencing on models. OWL is typically used to build ontologies (e.g. LRI-Core), which define the concepts of a certain domain.

So what does this have to do with Legal Texts?

By integrating MetaLex with the semantic web standards RDF, RDFS and OWL, we can transparently describe metadata both on the elements of legal texts themselves, and on the contents of those texts. For example, RDF structures can be used to integrate different manifestations of the same legal text, by using the standard Uniform Resource Identifier (URI) of MetaLex elements. Furthermore, RDF can be used to capture elaborate version management issues. OWL and RDFS can be used to describe the contents of legal texts: the concepts, but also their normative content. These semantic representations of legal texts can be used to performe elaborate legal reasoning, such as consistency checking, legal assessment etc. and for building knowledge-based applications which can be used by citizens to gain advice on complex legal issues.

The advantage of integrating the syntactic structure (i.e. plain MetaLex XML) with the semantic structure is that changes to a text can be immediately propagated to the depending (i.e. referring) texts and applications: an advanced legal content management system (see e.g. this paper).