The OWL Web Ontology Language Semantics and Abstract Syntax [OWL S&AS] document includes a presentation of an abstract syntax for OWL. The use of the term abstract syntax is somewhat of a misnomer, however, as the presentation is rather concrete. Not quite concrete enough, however, to fully describe a format that one can easily parse. In this document, we extend the grammar to provide a description of text-based concrete serialization for OWL ontologies.
This is a draft produced 10 December, 2003. Note that although this document relates to the OWL Web Ontology Language, it does not form part of the W3C WebOnt document set.
The OWL Web Ontology Language Semantics and Abstract Syntax [OWL S&AS] document includes a presentation of an abstract syntax for OWL. This is intended primarily as a mechanism to enable the definition of the formal semantics of the language along with the mapping into the normative concrete serialization in terms of RDF triples.
The use of the term abstract syntax is somewhat of a misnomer, however, as the actual presentation given is rather concrete. It is not quite concrete enough, however, to fully describe a format that one can easily parse. A standardised plain text ASCII format for serialization of OWL ontologies is likely to prove useful — for example for presenting small example ontologies in tutorial material. A similar approach has been taken with RDF, where N-Triples [N-Triples] provides a plain text format for encoding RDF graphs. In this document, we extend the grammar to provide a description of text-based concrete serialization for OWL ontologies. We follow the conventions adopted in N-Triples to cover URI references and literal values.An OWL Concrete Abstract Syntax document is a sequence of Unicode
characters encoded in UTF-8 defined by the grammar below. This
grammar is based on that given in [OWL
S&AS] with a number of extensions and a precise
definition for literals and URI references. We include a new
Namespace construct that relates a prefix to a
URI. Namespace constructs have document scope. The following
namespace prefixes are assumed to be predefined and can be used
without definition:
rdf = http://www.w3.org/1999/02/22-rdf-syntax-ns# xsd = http://www.w3.org/2001/XMLSchema# rdfs = http://www.w3.org/2000/01/rdf-schema# owl = http://www.w3.org/2002/07/owl#
Note that (unlike N3 grammars), we do not allow
the use of
_ as a prefix name.
The grammar is also available as a plain text file.
Below we present a simple example using the proposed syntax