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Re: [ALL] ODM Chapter review

From: Elisa F. Kendall <ekendall@sandsoft.com>
Date: Mon, 16 Jan 2006 09:01:25 -0800
Message-ID: <43CBD165.5020602@sandsoft.com>
To: SWBPD list <public-swbp-wg@w3.org>

Hi Gary,

Thank you so much for taking the time to read carefully - we really 
appreciate the feedback.
All of your comments are really very helpful, and point out places where 
we need clarification
at a minimum, if not changes to the model as well.  I'll forward this to 
the ODM team independently,
and will get back to you with the next version. 

FYI, and also for Bijan & Peter, since we have asked for their 
assistance, we have
elected to push the final submission out a few weeks so that we can 
incorporate more changes
such as your suggestions and also to allow us to test the QVT mappings.  
We did not want
to publish a document containing "mapping code" that had not been tested 
with the parsers
at a minimum, and only recently did such a tool become available.

Thanks again,


Gary Ng wrote:

>Sorry for the delay in sending these out. I took some extra time to read
>it more carefully.
>I have mainly focused on the OWL Chapter of [1], with some look ups into
>the DL and RDF Metamodel chapters. The original reference to the doc is
>at [2].
>The OWL descriptions are accurate. I believe it has covered all OWL
>constructs with minor quibbles. See "Quibbles" below with minor change
>Recap: Base on the OWL abstract syntax, the metamodel covers all
>language elements of OWL (OWLBase). The base model is a minimally
>constraining specification. The sub-language variants are achieved per
>application/vendor by constraining the usage of the elements, provided
>as additional contraint packages. The OWLDL and OWLFull Constraints
>Package have yet to be defined and I understand Peter Patel-S and Bijan
>are helping to define those. 
>Comment: Generally I find the interaction between RDF Document, OWL
>Graph, RDF and OWL statements, together with OWL Universe, needs some
>My concern can be summarized in the following questions, I find that the
>answers are probably implied within the text, but I haven't found
>satisfactory answers by myself and I need some help:
>1. It seems OWL Universe, OWL Statements and OWL Graph are meant to be
>derived objects that tool vendors are to support? No end-users will need
>to explicitly specify them?
>2. In 12.2.2: "As shown in Figure 14, an OWL ontology consists of a
>collection of facts, axioms, and annotations, defined in terms of zero
>or more RDF graphs and statements."
>     Can statements made in RDF that represent OWL Expressions readily
>translatable into OWLBase constructs? Can a resource graph specified in
>the RDF profile be readily usable as an OWL instance graph? 
>     From the other direction, RDFGraph contains RDF Statements.
>OWLGraph is a subset of RDFGraph. Not all graphs are valid OWL Graph.
>But does this mean that all OWL Expressions are also RDF Statements,
>just like the relationship between RDF and OWL syntax? Need to clarify
>that whether axioms and expressions made using OWL Metamodel has an
>equivalent RDF Statement form just like the language. 
>     But if the OWL Metamodel is based on the abstract syntax, which
>means it does not necessary correspond to the RDF syntax for axioms,
>which in turn would mean the OWL Ontology contains RDF Graphs + some
>objects which can only be accessed through OWL Universe?
>3. There seems to be two ways to specify an RDF triple? 
>     One is to use a Statement stereotype, the other is to literally
>associate one object to another with a link. The former allows
>reification, and associate the statement with a graph, the latter
>doesn't, and the fact that it becomes a statement is actually implicit.
>Or is it the case that all triples must be specified through a statement
>object with 3 links to subject, predicate, object explicitly, such that
>reification and or named graphs can be specified?
>4. Not really about the OWL MetaModel, but will we expect a rewrite of
>the DL MetaModel (Appendix C)? What is expected to be done with it? It
>looks like it still needs a lot of work.
>============================ Quibbles ============================
>Naming consistency: Suggest the names RDFGraph (for RDF) and
>OWLStatement (for OWL) rather than Graph (for RDF) and Statement (for
>OWL). Thus it is clear that there are: RDFGraph, RDFStatement, OWLGraph,
>12.3.6 Individuals
>SameIndividual and DifferentIndividual with associations sameIndividual
>and differentIndividual have not been introduced before or anywhere else
>in this chapter.
>12.3.11 OWLDataRange
>OWL DataRange can also be the rdfs:range of a Property but is missing
>here. It is certainly not in the RDF Metamodel and thus should be
>included here. 
>12.3.13 RDFProperty
>rdfs:domain and rdfs:range of property is covered in the RDFMetamodel
>and is not covered here. In the spirit of completeness, perhaps a
>pointer here to section 11.5.1 where they are described would be good.
>Since they are also an integral part of OWL.
>12.4 OWLBase Property
>Under the meta class Property, the siblings specified here are:
>FunctionalProperty, DatatypeProperty, ObjectProperty; Under
>ObjectProperty, there are InverseFunctional, SymmetricProperty, and
>I thought in OWL-Full DatatypeProperty may be InverseFunctional? The
>organization certainly suggests that if it is inverse functional, it is
>automatically object property, which is the case in DL. I went to
>checked the webont reference:
>   "NOTE: Because in OWL Full datatype properties are a subclass of
>object properties, an inverse-functional property can be defined for
>datatype properties. In OWL DL object properties and datatype properties
>are disjoint, so an inverse-functional property cannot be defined for
>datatype properties. See also Sec. 8.1 and Sec. 8.2."
>(thinking aloud here...) So to create an inverse functional Datatype
>property for OWL Full ontology from this meta model, one will have to
>declare that property as both inverse function and as datatype. As
>inverse functional prop is in turn an object property... the prop is
>both a datatype and object property => which is consistent with RDF and
>OWL-Full semantics. 
>Granted. No issue. But perhaps to include some explanation to reassure
>the reader that the semantics is correct with reference to WebOnt
>12.6 Datatypes
>Perhaps to explicitly mention that the OWL's notion of unsupported type
>is automatically handled too? 
>Doesn't need much description, as TypedLiteral and the RDFDatatype are
>already described in the RDFMetaModel. Again, this is more like just
>covering all OWL constructs like a checklist in this chapter rather than
>just leaving it implied in the TypedLiteral section. 
>12.2.3 RDFSLiteral
>This section seems out of place and interrupted the flow. Perhaps move
>to before or after 12.3.15 TypedLiteral?
>12.3 Class descriptions
>The alphabetical ordering of the sections on various annonymous classes:
>"ComplementClass, Enumerated, Intersection, Restriction, Union", could
>perhaps be arranged from simple (complement, intersection, union) to
>complex ideas (restriction)? It was slightly interrupting reading
>Intersection, then a detail long Restriction section, then back to
>Union, which carries similar content to Intersection.
>    "Vendors who are interested in supporting OWL Lite would simply use
>only the relevant constructs from the base package and tighted a few
>constraints from the OWL DL package, as required."
>Change "tighted" to "tighten" perhaps?
>[1] http://www.omg.org/cgi-bin/doc?ad/05-09-08.pdf
>[2] http://lists.w3.org/Archives/Public/public-swbp-wg/2005Nov/0174
Received on Monday, 16 January 2006 17:01:38 UTC

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