Joint Committee Minutes 22 May 2001

Participants

• Dan Connolly
• Mike Dean (joined late)
• Stefan Decker
• Frank van Harmelen
• Jim Hendler (joined late)
• Ian Horrocks
• Peter Patel-Schneider
• Lynn Andrea Stein

Announcements

Last Week's Minutes

DAML Layering

With respect to the Unique Names Assumption, Dan proposed to use daml:UnambiguousProperty as a form of cheap unique name. Peter notes that this is just locally unique.

With respect to the discussion on providing simplified idioms for common constructs that might also be otherwise representable in DAML+OIL, there was general consensus that providing such idioms is desirable. We're already providing some of these. We should document the equivalences.

We want to also document "recipes" such as this. RESOLVED: add unambiguousOver to our "candidates under consideration" list. ACTION (Mike): add a candidates page to http://www.daml.org/language/, as well as an FAQ section for idioms. Both should direct comments to the usual email lists.

With respect to Stefan's issue of an ontology container, Dan noted that rdfs:isDefinedBy is an existing mechanism to link classes and properties to an ontology if we need it. However, this has minimal value unless "everyone" uses it. Sergey Melnik has suggested that use of rdf:ID could automatically generate rdfs:isDefinedBy statements. Several folks liked this approach, but agreed that this is an issue for the W3C RDF Core WG.

Peter noted that an inference engine is likely required if a language includes enumerations and qualified number restrictions (this goes back to the first result in Description Logic).

Stefan noted that Level 1 should not require a DL reasoner, but should support transitive closure of simplified class definitions (named class or synonyms).

Jim Hendler suggested that we focus on an introductory subset (pragmatics) rather than computational complexity. He also advocated the use of use cases (e.g. using DAML to state proofs).

ACTION (Stefan): update layers proposal based on Dan's work, discussion, etc.

Next Week

We'll plan to review the existing DAML FAQ before making it public.

Dan suggested that we discuss what we expect to say about DAML+OIL at upcoming meetings including SWWS, the DAML PI meeting (July 18-20 in Nashua NH), etc.

Peter volunteered to write up a rules proposal.

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