Dan Connolly re-opened this topic at the end of the meeting. ACTION (Dan Connolly): figure out how to best transfer rights to W3C. If necessary, draft a letter for individual editors and authors to sign.
RDFS subclasses need no longer be proper.
Richard has also been looking at RQL, which provides a superset of the strawman proposal, including comparisons, non-monotonic operators (e.g. proper/direct subclasses), disjunctions, and negations.
RQL uses ^ syntactically to distinguish between
explicit assertions vs. inferences.
Forward-chaining reasoners may not keep track of explicit assertions vs. inferences.
Requiring this capability
may exclude some current reasoners.
Mike noted that conjunction (e.g. returning Californians or Texans) may be a difference between rules and queries. Providing multiple rules with partially common heads may be fine, but people generally want queries to be atomic for performance and other reasons.
A DAML Query should return the entailment based on DAML+OIL semantics.
There was discussion about query controls to support streaming/batching, etc.
and allowing the query engine to report that's all,
there might be more,
or
I have have more.
Several people felt this was a semantic issue and not just an
API/implementation issue.
Ignore the comment about the unique names assumption in the example distributed with the strawman proposal.
Frank noted that RQL is a strategic opportunity to (keep) the database community on-board. Squish, etc. are subsets of RQL, but without any inference/entailment (we might want to also support such queries on only asserted statements as a debugging feature if nothing else).
We could have multiple surface syntaxes on top of a DAML+OIL internal core representation (interlingua).
RQL may already be a W3C submission. ACTION (Frank): verify this, distribute URI.
ACTION (Richard): map strawman proposal to RQL
Richard noted that we need to identify criteria/requirements for a DAML+OIL query language. Ian raised the issue of cycles in variables, discussed more fully in his paper (cited by Richard) and its references.
Some of the issues can be addressed by documentation in the walkthru. For example, we want to show that it's allowable to use a property without defining it as such (but tools could properly flag this as a possible typo).
We should continue to include at least one instance (e.g. Adam) in the example to show that this is allowed, but may want to move other instances (Ian, Peter, etc.) to another page to show how ontologies and instances are normally separated.
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