Joint Committee Minutes 30 January 2001

Participants

• Tim Berners-Lee (joined late)
• Mike Dean
• Frank van Harmelen
• Pat Hayes
• Jeff Heflin
• Ian Horrocks
• Ora Lassila
• Deb McGuinness (joined late)
• Peter Patel-Schneider
• Lynn Andrea Stein

Announcements

As previously agreed, a public archive of the joint-committee email list is now available here.

Last Week's Minutes

Concrete Types

A few new points were raised:

• in RDF, an rdf:Property without a domain is unconstrained: it can take on either resource (abstract) or literal (concrete) values. The DAML+OIL(+CONCRETE) specification should address this case: there may be a middle ground between "disallowing" it in DAML+OIL, specifying that all results are undefined, and specifying a full semantics comparable to that for abstract and concrete properties.
• Frank: There is value in having some means of explicitly specifying that a property is unconstrained [e.g. AbstractProperty, ConcreteProperty, and HybridProperty as subclasses of rdf:Property] rather than just depending upon the absence of a constraint.
• Mike: In RDF and the current DAML+OIL, the domain of a property is always an abstract type. The ability to add properties to concrete types (e.g. integers) is a further language extension that would be best addressed (if at all) in a subsequent proposal. The current concrete types proposal(s) just deal with the range of properties.

Lynn asked how DAML+OIL is expected to relate to a future DAML-L. Some things we may want to do there may not be compatible with the current concrete types proposal. Most folks expect that there will be (occasionally incompatible) changes, and seemed to believe that we're working on a continuum of language revisions rather than a series of discrete languages.

Dan Connolly sent word (via Lynn) that he'd like more time to finish up his proposal (now about 2/3 done).

Deb withdrew her previous motion to vote today. Frank recommended that we not revisit this topic until additional formal proposals have been received and reviewed by the committee.

DAML PI Meeting

DAML+OIL plenary presentation

We have 90 minutes, to allocate as we see fit. Current thoughts:

What	Who	Minutes
Introduction	Mike	10
DAML+OIL goals/issues/experience	Ian	30
W3C Semantic Web Activities?	Tim/Ralph?	10
Model-Theoretic Semantics	Peter?	15
Axiomatic Semantics	Deb/Richard Fikes?	15
Q&A/overflow	everyone	10
TOTAL		90

Language breakout session

This is essentially a follow-up to the session at the DAML Kickoff meeting: a chance for the committee to get feedback from the user community (e.g. Dan King's comments) and discuss where we've been and where we're going. This will not be a formal committee meeting. Mike may have a simultaneous commitment as DAML Integrator -- if so, he'll ask others to moderate and take notes.

Birds-of-a-Feather (BOF) sessions

There will be 2 sessions with ~4 BOFs each. This is a chance for people with like interests to get together. BOFs will be less formal than the breakout sessions, and may or may not lead to follow-on activity. Benjamin Grosof will lead a BOF on DAML Rules, based on his early work with RuleML. Send suggestions for other BOFs to Mike.

The following folks indicated their plans to attend the PI Meeting:

• Tim Berners-Lee: no (Ralph Swick will be there; will try to call in)
• Dan Connolly: no (per Tim)
• Mike Dean: yes
• Pat Hayes: yes
• Jeff Heflin: yes
• Ian Horrocks: yes
• Frank van Harmelen: yes
• Ora Lassila: yes
• Deb McGuinness: yes
• Peter Patel-Schneider yes
• Lynn Andrea Stein: ? [missed response]

W3C membership and management is currently discussing a Semantic Web Activity. Everything will be announced at once (may or may not be before the PI meeting), with activities starting at that point.

In lieu of a telecon on February 13, we'll provide a speakerphone for the Language breakout session(s) on February 14 (exact time is or will be on the meeting agenda).

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