Tuesday, October 27, 2009

OWL 2 Support in TopBraid Composer

Following today's announcement that OWL 2 has become an official W3C recommendation, I am pleased to announce that TopBraid Composer 3.2 (to be published by the end of this week) has comprehensive OWL 2 support. Here is a sampler of some of the new capabilities.

Property Chain Axioms can be used to define relationships between multiple properties, for example to define that an uncle is the brother of a parent. In OWL 2 mode, TopBraid's Properties form contains a new widget for entering such property chains using owl:propertyChainAxiom. Another kind of new property axioms, owl:propertyDisjointWith can be edited on the same page.

User-Defined Datatypes are a mechanism of narrowing down datatype properties to specific value ranges, such as integer > 0. In typical cases, such datatypes are entered as allValuesFrom restrictions on the class form. We use the Manchester Syntax for that purpose:

In addition to class axioms, user-defined datatypes can also be used as global rdfs:ranges:

OWL 2 Class Axioms including qualified cardinality restrictions and all other features supported by the Manchester Syntax can be entered on the class forms:

All other OWL 2 extensions such as new property meta-classes, keys and syntactic sugar can be edited through the generic RDF editing capabilities of TopBraid - the extended OWL 2 system vocabulary has been very helpful for this. Of course, TopBraid Composer can load and save any OWL 2 file in formats such as RDF/XML or Turtle.

At the time of writing this, I am not aware of any OWL 2 compliant inference engines that we could freely distribute with TopBraid Composer. Currently available options include OWL RL engines such as SPIN or Oracle 11g RDF. I am sure more will follow, and anyone in the community is invited to contribute plug-ins to those inference engines that we cannot legally ship with our platform, as separate downloads.

The new OWL 2 support is available in all editions of TopBraid Composer, including the Free Edition.


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