See also: IRC log
- Bijan Parsia, Alan Ruttenberg, Boris Motik, Uli Sattler, Rinke Hoekstra, Markus Krötzsch, Michael Smith, Michael Schneider, Achille Fokoue, James Hendler, Carsten Lutz, Ratnesh Sahay, Peter Patel-Schneider, Jeremy Carroll, Ivan Herman, Sandro Hawke, Zhe Wu, Bernardo Cuenca Grau, Elisa Kendall, Evan Wallace, Vipul Kashyap, Martin Dzbor, Ian Horrocks, Jeff Pan
- JeremyCarroll will leave at XX.45, Peter Patel-Schneider will leave about 75 min in, Deborah McGuinness
- Alan Ruttenberg
- Carsten Lutz
The agenda was taken up in a non-standard order.
Peter Patel-Schneider: We did OWL Full because it was mandated.
Peter Patel-Schneider: I don't know if that is what you want to hear. I wont say who mandated it.
James Hendler: some people thought OWL should be DL'ish, others not
James Hendler: The key thing WebOnt decided, which is perhaps open to discussion, vocabulary terms like owl:X would be in both languages, although perhaps with restrictions on each. Each side had exactly the same vocabulary terms covered.
Jeremy Carroll: I felt what happened with OWL DL and Full, had to do with two different groups coming together. Peter represents the DL academic community, which had a strong idea where it was coming from. Meanwhile, there was an RDF community. Both communities can gain real insights from each other, but there are arguments and difference. Like any marriage, both sides have some good points and some bad points.
Bijan Parsia: It's a conceptual error to regard OWL Full as a unitary phenomenon. There are a lot of different parts to it, and they each have their own story. EG classes as instances. Very different uses cases. EG annotations. ("my property was made by me, and modified on some date" -- different from modeling.)
Bijan Parsia: I think there is an OWL Full is because there was to be a gap between what some people wanted and what some implementors (doing complete implemtnations) could do.
James Hendler: The path to the split was important. A lot of the design on the DL and Full sides were influenced by what happened when. We have the option to rationalize it now.
James Hendler: A lot depended on the temporal ordering of events. We now have the option to rationalize it.
Peter Patel-Schneider: Compatibility with RDF was requirement, and yet RDF Semantics weren't designed yet. If the ordering had happened differently, then the semantics of RDF might have been different. The FOL view of the world and the Triple view of the world were split. Once RDF settled on the Triple view, we had to live with it.
James Hendler: (60% of RDF data is FOAF, which is is not in DL)
Jeremy Carroll: People inside HP and out find great use for "reasonable" use of OWL-Full, eg subclass list vocabulary, but NOT "messing with the furniture". Having a rule engine as an underlying engine is important. [??]
Alan Ruttenberg: FOAF deviates from OWL DL in a few places. Inverse-functional-property on strings (eg mailbox hashes), and annotations on properties.
Alan Ruttenberg: I heard different descriptions of OWL full: Everything not in OWL DL. Or in terms of features. People don't often talk about OWL Full as a language with this and that features. Mostly they say they are in OWL full because they are not in OWL DL. Many people just want to use one or two features, does OWL full have to be a "whole" language?
Bijan Parsia: Think of OWL full as having several categories of addition: 1. notational variants of FO-constructs not in OWL DL, 2.: rules; 3.: metamodelling; 4: arbitrary graphs of b-nodes 5. non-simple riles in cardinality restrictions, 7. hilog semantics; 8. reflections on vocabulary [shadow builtins -- RDF List vs what you say about builtins should change meaning of ontologyes eg domain/range on rdf:type]
Bijan Parsia: Main use: push the bounds of OWL DL a bit to make their applications / tools fit; Semantic flexibility is nice, helps interoperability, but we shouldn't overformalize this
Michael Schneider: Great point of OWL full: accepts every RDF graph; people can have standard RDF data as used by SPARQL and incrementally add semantics to certain but not all properties. This gives you more flexibility than you have in OWL DL
Jeremy Carroll: One of the raisons d'etre of OWL Full is architectural. The RDF view puts semantics on top of triples, and 'semantic extensions' of RDF allow for multiple additional semantics to be layered on top. OWL Full is one of these. OWL Full includes OWL DL, I don't much like it being described as not OWL DL.
James Hendler: My users don't care about the semantics; they work operationally; they don't want to use OWL per se; they find OWL useful for some things they are doing; this applies to many people from the web 3.0 community. Using OWL DL forces them to use things they don't care about
James Hendler: Owl full is a misnomer; OWL Full is a vocabulary; OWL DL uses it
Bernardo Cuenca Grau: We should distinguish syntax and semantics; Jim's users want syntax
Bernardo Cuenca Grau: Do we only want an RDF syntax for OWL 1.1, or do we want also a semantics for the triples? If people only want syntax, they don't care about the semantics of the triples
Bijan Parsia: If users don't care in the semantics, do you see harm in assigning a semantics that is .... [??]
James Hendler: it's not that users don't care about the semantics; they care about the semantics of, say, same-as. But they don't care about provably getting their reasoners right. An axiomatic semantics may serve that community better than a model-theoretic semantics
Bijan Parsia: this is a presentational issue; I was asking for the actual semantics
James Hendler: It is important to get the semantics right, but people do it at their own risk; a good example is linking to another ontology without declaring the type.
Zhe Wu: some users are using OWL full features such as same as; they care about the semantics, have an intuitive understanding;
Alan Ruttenberg: we need to define a vocabulary, and a minimal operational semantics; a DL + feature semantics was proposed, without saying how all work together
Alan Ruttenberg: Is an OWL Full semantics along the lines of 1.0 something we want in this working group? Let's have a strawpoll.
Bijan Parsia: We should separate semantics presentation from semantics. I want to change the semantics of OWL full, and would like to stick with model theory for presentation
Jeremy Carroll: Clarifies Strawpoll: Do we want an Owl Full semantics as a delta of the OWL 1.0 full semantics?
Michael Schneider: People didn't understand what delta means here; we should explain before we can vote
ACTION: mschneid to explain what delta to 1.0 semantics means
Ivan Herman: I think we need to have a clear view of what the alternatives are before voting. We need a feeling what it costs in terms of time/energy. What would an operational semantics mean? We need this before making decisions.
ACTION: Alan to describe what he means by a "feature at a time" semantics
ACTION: hendler will describe an approach to an "operational semantics" for OWL Full
PROPOSED: Accept Previous Minutes
Action Item Review
Alan Ruttenberg: Peter is suggesting that we restore anonymous individuals as they existed; existential semantics. If we adopt skolemization, then go back and change it again
Michael Schneider: Has it really been existential semantics?
Peter Patel-Schneider: owl 1.0 was existential semantics; whether people implemented or not is separate issue
ACTION: pfps send out proposal for minimal change for issue-3
issue 68 postponed; should be discussed with Jeremy
Boris Motik: When you say there is no ontology property, do you mean there is no well-known ontology property, or there is no ontology property as such?
Rinke Hoekstra: We should add the builtin list of ontology annotations
Alan Ruttenberg: This is separate from the roundtripping issue, we should not treat them as one.
Boris Motik: We can easily mention the list of various anotation properties in the current documents. We could then close the issue potentially
Alan Ruttenberg: any objections?
ACTION: bmotik2 to Edit the secification to mention the well-known ontology properties in the spirit of OWL 1.0 and thus possibly resolve ISSUE-91
Peter Patel-Schneider: Simple way forward: state that the only facets allowable are those in XML schema datatypes; tiny change to the syntax
Peter Patel-Schneider: User-defined datatypes should have in the spec which facets make sense for them
Michael Smith: Agrees with peter
Boris Motik: You can currently put a datarange restriction on non-integers; difficult to implement; this should be changed; argument of datatype restriction should be a datatype
Michael Smith: That doesn't seem so important
Boris Motik: Issues with compatibility; is non-integer compatible with min-inclusive? Facets only on datatypes, not datatype expressions
James Hendler: We are formalizing things that are maybe better not formalized; lets go for a minimal solution and not fix how to handle the other cases at this point of time
Bijan Parsia: Some facets are always applicable; things that restrict the lexical form. Not very interesting to spec, though.
Michael Schneider: we could allow application to datatype expressions, as long as they are "compatible" with the facet
Ian Horrocks: Let's do something simple; hard to imagine that in application we need more than basic facets on basic datatypes; solution like in OWL 1.0: this is what we support, people can go beyond that but we don't spec it
Michael Schneider: I meant: table with fixed set of datatypes and fixed set of facets which described applicability
ACTION: smith to send email describing what may be lost if facets are only applied to datatypeURI
ACTION: bmotik2 to Change the spec to add a table with facet-datatype compatibility