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Re: Guide: Version for F2F

From: Leo Obrst <lobrst@mitre.org>
Date: Sat, 05 Oct 2002 10:35:18 -0400
Message-ID: <3D9EF8A5.A2190561@mitre.org>
To: Jeff Heflin <heflin@cse.lehigh.edu>
CC: "Smith, Michael K" <michael.smith@eds.com>, webont <www-webont-wg@w3.org>

Some comments below.

Leo

Jeff Heflin wrote:

> Hi Mike,
>
> Since I will be unable to attend the F2F, here are my comments on the
> Guide. In general, I think it is very good. I haven't had a chance to
> read over other feedback you got, so if there are duplicates here, I
> apologize.
>
> General Comments:
> -------------------
> - The sections should be numbered
>
> - You should use the common conventions for naming classes and
> properties. People will emulate the examples in this guide, so if you
> use upper case names for everything, that's what people will use
> everywhere. The RDF convention is to use mixed case to separate words in
> an identifier, and to begin class identifiers with capital letters and
> property identifiers with lower case letters.
>
> - You need a section called "Using Ontologies to Describe Data" (perhaps
> between Complex Property Axioms and Usage Examples). This section should
> point out that once an ontology is developed, you will want to describe
> data with it. It can mostly point back to the defining individuals and
> properties of individuals sections, but should have additional material
> on how ordinary documents import ontologies (this is of course still
> TBD). If you put in a placeholder, I'd be happy to contribute the text
> once imports is resolved.
>
> - Assuming we resolve the versioning issues, you'll also need a section
> on "Versioning Ontologies." Once again, I'd be happy to contribute the
> text once the WG agrees on a solution.
>
> Detailed comments:
> ---------------------
> - I think the short history is fine
>
> - The WG should think about whether it wants to advertise particular
> companies (e.g., VerticalNet) in its official documents. I feel
> uncomfortable with this. With the case in point, I think we can talk
> about e-commerce in the abstract without losing much from the document

I would exclude the specific reference to VerticalNet and just use B2B
(business-to-business) e-commerce. Primarily because this is not now accurate.
VerticalNet sold off its 59 verticals and is now a software provider, rather
than directly a B2B company. I know, because I ran the ontology dept. there
until the dot.com burst.


>
>
> - In "The structure of ontologies", last sentence: define "entailed"
>
> - Once the imports and versioning issues have been resolved I'll suggest
> some changes to the "Ontology Headers" section
>
> - In "Defining simple hierarchical named classes" (5th paragraph) you
> say how rdf:resource and rdf:about can be used to refer to names. You
> should explain the resource is used in properties and about is used with
> class membership
>
> - Same section, next paragraph: "...permits the extension of the
> imported definition of x without modifying the original resource" Do you
> mean ontology instead of resource?
>
> - Same section, paragraph 8, "it is always possible to reference a
> resource using its full URI..." You should say that when referencing
> with "resource" or "about" to something from another namespace, you must
> use the full URI. You can only use namespace abbreviations when the
> class or property is an element name.
>
> - In "Defining individuals", 2nd example. type should be prefixed by
> "rdf:" Can't have "VIN:" in the about or resource attribute values
>
> - Same section. You should mention what rdf:type means, thus explaining
> why the two examples are equivalent.
>
> - In "Simple Properties - Defining Properties" Explain in words what a
> domain and range are. Point out that because the Web is an open world,
> these are not used to check data, but instead to infer things. For
> example, if I have W as the subject of a "made-from-grape" predicate but
> do not state that W is a Wine, this is not an error, but instead leads
> to the inference that W must be a Wine. It is only an "error" if this
> inference leads to a logical contradiction. Also mention that multiple
> domains or ranges mean the domain or the range is the intersection of
> all such classes.
>
> - Same section, 6th paragraph: Say what "subPropertyOf" means
> generically.
>
> - Same section, 8th paragraph, "The first subClassOf defines an un-named
> class...": I think you mean "second subClassOf". The first is just a
> subclassof potable-liquid.
>
> - In "Property Characteristics and Restrictions": Shouldn't the axiom
> for TransitiveProperty  be "P(x,y) and P(y,z) -> P(x,z)", not iff? Iff
> would imply that for any value pair there was some intermediate value
> that links them, implying that all such properties would have to have an
> infinite set of values or at least be symmetric.
>
> - Same section: Give generic plain English definitions for each of
> TransitiveProperty, SymmetricProperty, FunctionalProperty, and
> InverseFunctionalProperty. Add syntax examples for each (except
> inverseOf, which you already have.
>
> - In "Property Restrictions- allValuesFrom, someValuesFrom": give plain
> English descriptions of the meanings of these terms
>
> - In "Cardinality", you say "We have already seen examples of
> cardinality constraints." Is this right? I didn't see any previous
> examples of cardinality constraints.
>
> - In "Set Operators", pargraph 4, "Classes can be identified as
> closed...": I think this paragraph would be better stated by saying
> something like "The intersectionOf operator takes the intersection of a
> list of classes. Since the Semantic Web is assumed to be open, it is
> important to explicitly state that this list is closed, i.e., all of its
> members are listed. The rdf:parseType="collection" attribute is an RDF
> trick for stating that the content of an element is a closed list of RDF
> resources. In this case, a list of classes."
>
> - Same section, last example about FRUIT with two subclasses: We should
> be clear that this does not have the same meaning as intersectionOf, it
> says that Fruit is a subclassOf the intersection of SweetFruit and
> NonSweetFruit (i.e., it might be smaller than the intersection). Unlike,
> the intersectionOf operator, there might be some instances in this
> intersection which are not Fruit. I also think this example should be
> moved immediately after we discuss intersectionOf, instead of after
> Union.
>
> - In "Disjoint Classes", last example: You ask if it is permitted. I
> don't think so. First of all, having oneOf as a subelement to
> disjointWith violates RDF striping rules (a class should go here). Now
> if you wrap the oneOf in <Class>  and </Class> tags, it should be okay
> as far as RDF is concerned but I don't think it will have the meaning
> you intended. First of all, oneOf takes a list of instances as its
> arguments, but you are providing classes. Whether or not this is legal
> depends on the resolution of one of our outstanding contentious issues
> (classes as instances). However, let's assume it is resolved in favor of
> classes as instances. Then I would think it means that the classes MEAT,
> FOWL, etc. cannot be members of EDIBLE-THING, but does not say anything
> about their instances. That is, if Beef was a type of Meat then it could
> also be a type of Pasta without contradicting your definition, but MEAT
> could not be a type of Pasta.
>
> - In "Complex Property Axioms": You say that if you combined the two
> restrictions it would "imply that all burgundies are dry" but the first
> restriction already does this alone (i.e, every burgundy must have a
> "Dry" value for SUGAR). It seems that the second restriction only says
> that they can't have any other values as well.
>
> - In "Usage Examples" I have the same uneasiness about referencing
> particular wine portals in a W3C spec. Is it really necessary?
>
> - I'm not sure if the "Wine Agent" example adds a whole lot of value to
> the document.
>
> - In "Appendix B": I think the syntax for saying hasSubArea is a
> transitive property should be:
>
> <owl:ObjectProperty rdf:ID="hasSubArea">
>    <rdf:type resource="http://www.w3.org/??/owl#TransitiveProperty">
> </owl:ObjectProperty>
>
> Jeff
>
> "Smith, Michael K" wrote:
> >
> > I am not sure how 2 guides got in there.  A slip of the mouse.
> > Here is what should have been included:
> >
> >  <<Guide.html>>  <<wines.owl>>
> > - Mike
> >
> >   ------------------------------------------------------------------------
> >                  Name: Guide.html
> >    Guide.html    Type: Hypertext Markup Language (text/html)
> >              Encoding: quoted-printable
> >
> >                        Name: wines.owl
> >    wines.owl           Type: unspecified type (application/octet-stream)
> >                    Encoding: quoted-printable
> >             Download Status: Not downloaded with message

--
_____________________________________________
Dr. Leo Obrst  The MITRE Corporation
mailto:lobrst@mitre.org Intelligent Information Management/Exploitation
Voice: 703-883-6770 7515 Colshire Drive, M/S W640
Fax: 703-883-1379       McLean, VA 22102-7508, USA
Received on Saturday, 5 October 2002 10:35:43 GMT

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