% very short version of warning label section -- v6 % for insertion as additional section in the OWL Rules draft % 10/16/03 % by Benjamin Grosof % based on consensus from 10/14/03 Joint Committee telecon % with edits input from Mike Dean, Ian Horrocks, Peter Patel-Schneider 6. Usage Suggestions; Extensibility and Interoperability Cautions Users may want to restrict the form or expressiveness of the rules they employ, in order to increase interoperability, reusability, extensibility, computational scaleability, or ease of implementation. A useful restriction in the form of the rules is to limit antecedent and consequent classAtoms to be named classes, where the classes are defined purely in OWL (in the same document or in external OWL documents). Adhering to this format makes it easier to translate rules to or from existing (or future) rule systems, including: 1) Prolog; 2) production rules (descended from OPS5); 3) event-condition-action rules; and 4) SQL (where views, queries, and facts are all rules). Adhering to this form also maximizes reuse and interoperability of the ontology knowledge in the rules with other OWL-speaking systems that do not necessarily support OWL Rules. Users also may want to restrict the expressiveness of the OWL classes and descriptions appearing in rules. One useful restriction on expressivity is Description Logic Programs [Grosof et al 2003] which, e.g., prohibits existentially-quantified knowledge in consequents. Suitably-restricted OWL Rules can be straightforwardly extended to enable procedural attachments and/or nonmonotonic reasoning (negation-as-failure and/or prioritized conflict handling) of the kinds supported in CCI rule systems and in RuleML [RuleML] which facilitates interoperability between those CCI rule systems. Such adherence may thus facilitate combining OWL Rules knowledge with knowledge from those other rules languages. Suitable restrictions can also improve the empirical tractability of reasoning with rules. A longer, more detailed version of the above suggestions (alias "warning label") is available. Additional References: [Grosof et al 2003] Description Logic Programs: Combining Logic Programs with Description Logic. Benjamin Grosof, Ian Horrocks, Raphael Volz, Stefan Decker. Proc. WWW2003, Budapest, May 2003. http://www2003.org/cdrom/papers/refereed/p117/p117-grosof.html; also http://ebusiness.mit.edu/bgrosof/#DLP. [RuleML] Rule Markup Language Initiative. http://www.ruleml.org