Joint Committee Minutes 16 January 2001

Participants

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

Announcements

We'll start regularly running an Internet Relay Chat (IRC) session in parallel with the telecons. Connect to channel #joint-committee on www.daml.org:6667.

www.daml.org will be moving to a new server and IP address over the next week or so. Details and schedule are forthcoming.

Last Week's Minutes

DAML+OIL

In response to feedback already received:

• Several typos in daml+oil.daml have been fixed.
• RESOLVED: Disjoint will be removed in the next language revision.
• Late comment related to replacing Disjoint with disjointUnionOf: we may want to rename disjointUnionOf to be disjointPartitionOf. We'll discuss this next week.

Concrete Types

A few clarifications during Ian's presentation:

• rdf:Property could be a parent of ConcreteProperty and AbstractProperty
• DAML+OIL lists would be used for abstract instances; XML Schema lists for concrete instances
• Dan Connolly commented that XML Schema types are currently identified by a URI, name pair; URI#name is currently only used within the RDF community.
• maxCardinality, etc. would probably not be treated as a ConcreteProperty, but as a special language construct
• this proposal is essentially agnostic with respect to representation -- it could be modified to prescribe use of XML Schema

• lexical identification of types (e.g. float vs. int vs. string, without need to consult schema)
• mixing concrete and abstract instances (e.g. in lists)
• ability to define subtypes such as odd integers at the DAML+OIL level (ability to reason over types in DAML+OIL space)

• ACTION (Ian Horrocks): refine proposal and add example syntax using XML Schema. Post updated proposal to www-rdf-logic to stimulate external discussion.
• ACTION (everyone): review Dan's thoughts. He's currently stuck on some hard issues.
• ACTION (Dan Connolly): post thoughts to www-rdf-logic to stimulate new ideas.

Upcoming Topics

• DAML+OIL Graph Model (if any): ideas from Conceptual Graphs, extensions to RDF graph model, etc.
• revisit DAML Collections following removal of Disjoint, etc.
• replace disjointUnionOf with disjointPartitionOf
• axiomatic semantics (defer to February 6 so Deb and Richard can participate): further semantics for lists (e.g. equality, can a list contain itself)

Links