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Re: Review of QRG

From: Jie Bao <baojie@cs.rpi.edu>
Date: Tue, 5 May 2009 21:53:15 -0400
Message-ID: <b6b357670905051853y12118afdia5ec51286a45bb1c@mail.gmail.com>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: public-owl-wg@w3.org

Thanks for the review.

I made revisions based your and Ian's suggestions. There is the diff
to the last announced version (May 2)


There are some pending issues we might discuss tomorrow.

Details are inline


On Sun, May 3, 2009 at 2:03 PM, Peter F. Patel-Schneider
<pfps@research.bell-labs.com> wrote:
>        Review of QRG
> I reviewd the version of 3 May 2009.
> I fixed a number of typographical and grammatical errors.
> Some of the suggestions require major changes to the document so a
> re-review will be needed.
> Data Property Restrictions
>     individual value -> literal value

> 4.1: There is no "hook for n-ary datatype" in Data Ranges
I'm still not sure about not mentioning it at all as a new feature,
but I won't fight for it, unless there are other voices in the WG.

> 4.1: Annotation of objects was in OWL 1
It is slightly different. In OWL 2, AnnotationAssertion can be used as
an axiom to add annotation to any IRI, even if the IRI is not an
entity. OWL 1 annotation does not provide such an ability. Thus, I
changed the wording "Annotation of an object" => "annotation

> 4.1: Annotation of annotations is new in OWL 2
"annotation of an axiom" => "annotation of an axiom or an annotation"

> 4.1: There are many extra built-in datatypes beyond the ones listed.

for easy of tracking, I copy the exchange from other mail

Jie: The current list is the diff of [1] (OWL 2) to [2] (OWL 1). What
are other extra built-in datatypes?
   [1] http://www.w3.org/2007/OWL/wiki/Syntax#Datatype_Maps
   [2] http://www.w3.org/TR/owl-semantics/syntax.html

Peter: The only true built-ins in OWL 1 are xsd;integer and
xsd:string.  all others were optional, and only lightly implemented
(if at all).

However, quote from [2]

"The following XML Schema datatypes [XML Schema Datatypes] can be used
in OWL as built-in datatypes by means of the XML Schema canonical URI
reference for the datatype, http://www.w3.org/2001/XMLSchema#name,
where name is......"

It is not stated in the OWL 1 syntax specification that xsd:integer
and xsd:string are "true" built-ins and the others are optional.
Whether some of them are lightly implemented does not change the

> 2.4: datatype definitions are a kind of axiom
Created a new table "Data Range Axioms"

> 3.1: xsd:dateTime allows the absence of time zone offset
>     xsd:dateTimeStamp requires time zone offset

> 2.3: anonymous individuals are written _:a

> 2.8: The section on annotations has several errors:
>     - there are annotation assertions
>       - which can be on any IRI or anonymous individual
>       - which have value any IRI, anonymous individual, or literal

>From your another email

"The "i.e." clause in QRG is incorrect and should be removed."

I suppose you mean the "(e.g., a named ontology, class, datatype,
property or individual) " clause - I think it will help users to
realize annotation is applicable to those things. Thus I prefer to
keep the clause.

>     - there are annotations on axioms
>       - if the axiom has a main blank node
>          then the annotation triple is on that blank node
>       - if the axiom generates one or more main triples
>          then four triples sharing a blank node are added for each main
>          triple
>           the annotation generates a triple on each blank node
>     - there are annotations on annotations
>       - four triples sharing a blank node are added for the annotation
>        the new annotation triple is on this blank node

>From your other email: "You allow ontologies in Section 2.8, which is
not correct.  Ontology
annotations should be handled uniformaly in Section 2.9."

However, from the Syntax definition:

ontologyAnnotations := { Annotation }
axiomAnnotations := { Annotation }

I do not see a special way that ontologyAnnotations should be
represented differently from axiomAnnotations. Thus we might not need
to repeat the information.

> 2.9: The functional syntax for the three annotation properties is wrong.
The section title is changed to "Built-in Annotation Properties for Ontologies"

The Functional Syntax is simplified as just their names, to be
consistent with 2.8

> 2.9: The three annotation properties here should be added to the list of
>     annotation properties in 2.8
There needs some discussion at telcon. I copy the argument from the other email

Jie: {{
> that is the part confuses me (maybe many other users as well). In
> Syntax, they are defined as annotation properties. In RDF semantics,
> then they are introduced as "Ontology Properties" (which is a
> completely new concept w.r.t. Syntax).
> In syntax, they are again mentioned in " Ontology Annotations" with
> notice "The usage of these annotation properties on entities other
> than ontologies is discouraged. "

> It looks a difference between the Syntax and the RDF Semantics. If the
> QRG is a guide to OWL 2 in general (not only OWL DL), then we might
> need to introduce "Ontology Properties".

Peter: {{
 Syntax is supposed to cover essentially all of OWL 2, and should be
considered the target for QRG.

My suggestion is that in QRG to just make them all be annotation
properties and ignore the "discouragement".

More remark (Jie):

There are indeed OWL 2 Full features not covered by Syntax  (ontology
properties is an example).

> 2.0: There are no links to NF&R in the first column.

> I suggest that the notation situation be cleaned up as follows:
> - rename Section 1 to  Names, Prefixes, and Notation

>  Names in OWL 2 are IRIs, often written in a shorthand PF:LCL, where PF
>  refers to an IRI forming the first part of the name and LCL is the
>  remainder of the name.  Throughout this document U is any IRI, CN is a
>  class name, DN is a datatype name, PN is an object property name, RN
>  is a data property name, AN is an annotation property name, aN is an
>  individual name, and ON is an ontology name.
Done, with one exception: is an annotation property always an
annotation property name? I didn't see a way to construct an unnamed

The same for RN.

AnnotationProperty := IRI
DataProperty := IRI
DataPropertyExpression := DataProperty

AN and RN were not used anyway even if they were introduced.

>  OWL 2 individuals can also be globally anonymous, written as _:a where
>  a is the local identifier for the individual.
>  Throughout the document C is a class expression, D is a data range, P
>  is an object property expression, R is a data property expression, a
>  is an individual, v is a literal, n is a ....
>  In the RDF syntax, _:x is a blank node and (a1...an) is an RDF list.
>  All of the previous can have subscripts.

The new section is:

> - remove the paragraph on notation from Section 2.0


> - make the appropriate changes throughout the rest of the document


> 2.1: n-ary Data Ranges do not need to be in this document
Quote myself from above: "I'm still not sure about not mentioning it
at all as a new feature, but I won't fight for it, unless there are
other voices in the WG."

> 2.8: The section on deprecation is not needed and should at least be
>     moved to an appendix.
My idea is, having an extra subsection called "Additional Vocabulary
in OWL 2 Full", with all OWL 1 (including deprecation) and RDF
vocabulary that not in FS->RDF but can be used in OWL 2 Full, with
links to their originally
definitions (like rdf:Statement in the example)


Again, I think QRG should not be limited to Syntax and attract OWL 2
Full users as well. Moving those features to appendix will make them
as a second-class citizen.

> 2.4: The comment that datatypes have arity one is not needed.
OK, removed (with some reservation - that distinction at least has
confused me for a couple of days earlier)

> 3.2: The introductory paragraphs are not needed.  For the second, just
>     use the same terminology in 3.1 and 3.2.
Both removed

> 3.2: The explanation column is not needed.
that maybe a matter of taste. I would think they are quite helpful
(esp. for that facet is a completely new notion in OWL 2)

> 3.2: "whose value is a" -> "as a"

I also swapped "Value" and "Applicable Datatypes" columns based on
Ian's suggestion.

> 4.1: this can be drastically shortened by not using lists
while it is true many of the items can be shortened or combined,
completely getting rid of list might make the table less readable. As
they will not go to the print version anyway, space should not be an

> 4.1: many of the items in the list can be shortened
>     - remove "(self restriction)"
this one is called as " Self-Restriction" in Syntax and NF&R. It was
originally also called so in QRG, but was changed to "local
reflexivity" which is supposed to more apprehensible.  Keeping both
might help users to refer other documents.

>     - remove "restriction" where it is implied
I tried to combine many similar items, e.g.,

object qualified exact/maximum/minimal cardinality restriction
data qualified exact/maximum/minimal cardinality restriction
object and data qualified exact/maximum/minimal cardinality restriction

>     - remove "binary and pairwise"
> 4.1: All facets are new to OWL 2, so just say so, don't list them.
OK. Moved "facets" as a single item under "Data Ranges"

Jie Bao
Received on Wednesday, 6 May 2009 01:53:56 UTC

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