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Re: Mustangs vs myMustang

From: Richard H. McCullough <rhm@volcano.net>
Date: Thu, 20 Oct 2005 00:39:08 -0700
Message-ID: <001c01c5d549$bb89b420$0100000a@rhm8200>
To: "Teijgeler, Hans" <hans.teijgeler@quicknet.nl>
Cc: <jos.deroo@agfa.com>, <semantic-web@w3c.org>, "'West, Matthew'" <matthew.west@shell.com>, "'Paap, Onno'" <onno.paap@ezzysurf.com>

Hi Hans
I'll admit I missed some of the "middle" of this long string of emails
about "Mustangs vs. myMustang".  I'll try to catch up all at once.

1,2. I think "singleton class" is bad because it's just "pretending"
that an Individual is a Class.  It's bound to get you in trouble
sooner or later.

3. "It" is the "Ford Company", and "where" is wherever you
were going to "publish" the class.  Are you telling me that
individuals can't be published there?  Back to the "real problem"
in a minute.

4. I know OWL can deal with individuals, but I thought you
did not because you seemed to be saying that all classes
have to be defined in OWL, and all individuals have to be
defined in RDF.  Isn't RDF a semantic subset of OWL?

Back to the "real problem".  I believe you said below that
no OWL property can relate an individual to a class.
I think that is false, but I am not an OWL expert.
If it is true, I think OWL should be changed.

The only thing I remember hearing along these lines
is that owl:ObjectProperty relates individual to individual.
But owl:ObjectProperty is just one subClassOf owl:Property.
There ought to be some subClassOf owl:Property which relates
individuals to classes.

Dick McCullough
knowledge := man do identify od existent done;
knowledge haspart proposition list;
http://rhm.cdepot.net/
----- Original Message ----- 
From: "Hans Teijgeler" <hans.teijgeler@quicknet.nl>
To: "'Richard H. McCullough'" <rhm@cdepot.net>
Cc: <jos.deroo@agfa.com>; <semantic-web@w3c.org>; "'West, Matthew'" 
<matthew.west@shell.com>; "'Paap, Onno'" <onno.paap@ezzysurf.com>
Sent: Wednesday, October 19, 2005 10:52 PM
Subject: RE: Mustangs vs myMustang


> Hi Dick,
>
> Your four sentences give rise to four questions:
> [RM] I strongly recommend that you do NOT use "singleton classes".
> [HT] Why? What's wrong with singletons?
>
> [RM] Your "singleton class" IS AN INDIVIDUAL!!!
> [HT] Yes. So?
>
> [RM] Just give it a unique name that everyone can use.
> [HT] What is "it", and where is that unique name published? The problem is
> not the name (see below)
>
> [RM] What makes you think that OWL cannot deal with individuals?
> [HT] What makes you think that I think that?
>
> The only reason for suggesting a singleton class was to solve the
> "crossover" Property isManufacturerOf between the individual FordCompany 
> and
> the class "Mustang".
>
> For what I understand of the relationship between RDFS/OWL and RDF is that
> the only Property that can link the two domains is rdf:type.
>
> So there seem to be two possbilities to tell that the FordCompany is the
> manufacturer of cars that are called Mustang:
>
> 1. define everything in the OWL Class domain, which means that we have to
> create a singleton class for FordCompany, and relate that to the class
> 'Mustang'
>
> 2. define everything in the OWL individual domain, which means that we 
> have
> to create an (OWL) individual for the class 'Mustang' (the "class 
> extension"
> ?), and relate that to the individual FordCompany.
>
> Regards,
> Hans
>
> -----Original Message-----
> From: Richard H. McCullough [mailto:rhm@volcano.net]
> Sent: Thursday, October 20, 2005 12:58 AM
> To: Hans Teijgeler; jos.deroo@agfa.com
> Cc: 'Paap, Onno'; semantic-web@w3c.org; West, Matthew
> Subject: Re: Mustangs vs myMustang
>
> I strongly recommend that you do NOT use "singleton classes".
> Your "singleton class" IS AN INDIVIDUAL!!!
> Just give it a unique name that everyone can use.
>
> What makes you think that OWL cannot deal with individuals?
>
> Dick McCullough
> knowledge := man do identify od existent done;
> knowledge haspart proposition list;
> http://rhm.cdepot.net/
> ----- Original Message ----- 
> From: "Hans Teijgeler" <hans.teijgeler@quicknet.nl>
> To: <jos.deroo@agfa.com>
> Cc: "'Paap, Onno'" <onno.paap@ezzysurf.com>; <semantic-web@w3c.org>; 
> "West,
> Matthew" <matthew.west@shell.com>
> Sent: Tuesday, October 18, 2005 2:22 AM
> Subject: RE: Mustangs vs myMustang
>
>
>>
>> Hi Jos and Geoff,
>>
>> Forgive me my ignorance, but could you please translate:
>>
>> :FordCompany rdf:type [a owl:Restriction;
>>                 owl:onProperty :isManufacturerOf;
>>                 owl:someValuesFrom :Mustangs].
>>
>> into RDF/XML? As a newcomer RDF/XML is clearer to me than the above code
>> (I
>> am not one of the seemingly many RDF/XML bashers, probably because it was
>> the first I learned to use).
>>
>> Not to seem lazy, I'll give it a try myself:
>> I first define the class:
>>
>>    <owl:Class rdf:ID="MustangManufacturer">
>>        <rdfs:subClassOf rdf:resource="#CarManufacturer"/>
>>        <owl:Restriction>
>>            <owl:onProperty rdf:resource="#isManufacturerOf" />
>>            <owl:someValuesFrom rdf:resource="#Mustang" />
>>        </owl:Restriction>
>>    </owl:Class>
>>
>> and then the individual Ford Company that is typed with above anonymous
>> class:
>>
>>   <owl:Thing rdf:ID="FordCompany"/>
>>    <owl:Thing rdf:about="#FordCompany">
>>        <rdf:type rdf:resource="#MustangManufacturer"/>
>>    </owl:Thing>
>>
>> QUESTIONS:
>> 1. is this code correct?
>> 2. Could I, instead of the class MustangManufacturer also define a
>> singleton
>> class FordCompany? (that wouldn't help in this case, because it is
>> possible
>> that other companies manufacture Mustangs in licence). The advantage,
>> however, of defining that singleton would be that I can define everything
>> about FordCompany at OWL-level, and where necessary cross over to RDF
>> later.
>> That singleton, if defined at some central server, could avoid using
>> hundreds of URIs for the same company (we call that a "reference
>> individual", also defined for geographical objects (e.g. London,UK) )
>> 3. How do you define that a class is a singleton?
>>
>> Regards,
>> Hans
>>
>>
>> -----Original Message-----
>> From: semantic-web-request@w3.org [mailto:semantic-web-request@w3.org] On
>> Behalf Of jos.deroo@agfa.com
>> Sent: Tuesday, October 18, 2005 2:36 AM
>> To: hans.teijgeler@quicknet.nl
>> Cc: 'Paap, Onno'; semantic-web@w3c.org
>> Subject: RE: Mustangs vs myMustang
>>
>>
>> There is nothing alarming about making a distinction between the thing 
>> and
>> its extension and allowing things to belong to (even their own) 
>> extension.
>> I really like that very much; still for your case my take would be
>>
>> :isManufacturerOf rdfs:domain :Manufacturer; rdfs:range
>> :ManufacturedGoods.
>>
>> plus
>>
>> :Mustangs rdfs:subClassOf :ManufacturedGoods.
>> :myMustang rdf:type :Mustangs.
>> :FordCompany :isManufacturerOf :myMustang.
>>
>> and have Geoff's
>>
>> :FordCompany rdf:type [a owl:Restriction;
>>                 owl:onProperty :isManufacturerOf;
>>                 owl:someValuesFrom :Mustangs].
>>
>>
>> -- 
>> Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
>>
>>
>>
>>
>> "Hans Teijgeler" <hans.teijgeler@quicknet.nl>
>> 17/10/2005 07:59
>>
>>
>>        To:     Jos De_Roo/AMDUS/MOR/Agfa-NV/BE/BAYER@AGFA
>>        cc:     "'Paap, Onno'" <onno.paap@ezzysurf.com>,
>> <semantic-web@w3c.org>,
>> <semantic-web-request@w3.org>
>>        Subject:        RE: Mustangs vs myMustang
>>
>>
>> Hi Jos,
>>
>> Thanks!
>>
>> Your last sentence: " That is indeed *possible* in RDF and OWL Full"  is
>> rather alarming to me as being seen by you as substandard.
>>
>> If this were to comply with the constraints of OWL DL, how should I model
>> it? (your assumption about the base URI was correct).
>>
>> Regards,
>> Hans
>>
>> -----Original Message-----
>> From: jos.deroo@agfa.com [mailto:jos.deroo@agfa.com]
>> Sent: Sunday, October 16, 2005 2:32 PM
>> To: hans.teijgeler@quicknet.nl
>> Cc: 'Hans Teijgeler'; 'Sullivan, Jan'; 'West, Matthew R SIPC-OFD/321';
>> Paap,
>> Onno; semantic-web@w3c.org; semantic-web-request@w3.org
>> Subject: RE: Mustangs vs myMustang
>>
>>> From the beginning I have struggled with chapter 3.1.3 of the OWL Guide.
>>
>> So let me ask this question: If I have:
>>>
>>>    <owl:Thing rdf:ID="Mustang"/>
>>>    <owl:Thing rdf:about="#Mustang">
>>>        <rdf:type rdf:resource="http://www.example.org/library#Mustang"/>
>>>    </owl:Thing>
>>>
>>> then does this mean that I have here the class extension?
>>
>> What is the base URI for that rdf:ID="Mustang"?
>> If it is http://www.example.org/library#
>> then
>>
>> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>>          xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
>>          xmlns:owl="http://www.w3.org/2002/07/owl#"
>>          xml:base="http://www.example.org/library#">
>>
>>    <owl:Thing rdf:ID="Mustang"/>
>>    <owl:Thing rdf:about="#Mustang">
>>        <rdf:type rdf:resource="http://www.example.org/library#Mustang"/>
>>    </owl:Thing>
>>
>> </rdf:RDF>
>>
>>
>> is saying that
>>
>> :Mustang rdf:type :Mustang.
>>
>> or saying that :Mustang is in it's own extension
>> (and :myMustang is also in that extension)
>> That is indeed *possible* in RDF and OWL Full
>>
>>
>>
>> -- 
>> Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
>>
>>
>>
>>
>>
>>
>>
>
>
> 
Received on Thursday, 20 October 2005 07:45:12 UTC

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