RE: Interpretation of RDF reification

Dear All,

Starting with:

[Brian]:
> It seems like there should be some property that relates the class
> Married to the property married.  It would seem that husband and wife
> properties are distinguished in relation to Married and married from
> properties like startDate and endDate.
[Peter]:Well, if you want to go to FOL or an expressive ontology language
you could do most of this, but RDF hasn't anywhere near the expressive power
required.

and trying to avoid the impression of beating the same drum over and over
again, this is a typical example where ISO 15926 has the solution for.  

We enhanced the expressive power of RDF/RDFS/OWL by adding such an
"expressive ontology language", the ISO 15926-2 generic data model [1].

We then have an ISO 15926 entity type, mapped to an OWL Class, called
"Relationship", with many subclasses such as Composition (with Properties
'whole' and 'part'), Connection, Containment, and more esoteric ones like
FunctionalMapping, LowerBoundOfNumberRange, etc.

We also can create user-defined Relationship classes.

Although Marriage typically is not in our domain of interest we could easily
come up with such a Relationship class, as shown below. Mind you, this is
rather verbose (for a great part caused by RDF/XML), but always using the
same structures:

    <owl:Class rdf:ID="Marriage">
        <rdfs:subClassOf
rdf:resource="http://www.15926.org/rd/2005-11#RELATIONSHIP"/>
        <rdfs:subClassOf>
            <owl:Restriction>
                <owl:onProperty rdf:resource="#partner1"/>
                <owl:allValuesFrom
rdf:resource=http://www.15926.org/rd/2005-11#PERSON/>
            </owl:Restriction>
        </rdfs:subClassOf>
        <rdfs:subClassOf>
            <owl:Restriction>
                <owl:onProperty rdf:resource="#partner2"/>
                <owl:allValuesFrom
rdf:resource="http://www.15926.org/rd/2005-11#PERSON"/>
            </owl:Restriction>
        </rdfs:subClassOf>
    </rdfs:Class>

    <owl:Class rdf:ID="HeterosexualMarriage">
        <rdfs:subClassOf rdf:resource="#Marriage"/>
        <rdfs:subClassOf>
            <owl:Restriction>
                <owl:onProperty rdf:resource="#partner1"/>
                <owl:allValuesFrom
rdf:resource=http://www.15926.org/rd/2005-11#MALE/>
            </owl:Restriction>
        </rdfs:subClassOf>
        <rdfs:subClassOf>
            <owl:Restriction>
                <owl:onProperty rdf:resource="#partner2"/>
                <owl:allValuesFrom
rdf:resource="http://www.15926.org/rd/2005-11#FEMALE"/>
            </owl:Restriction>
        </rdfs:subClassOf>
    </rdfs:Class>

    <owl:Class rdf:ID="Happy">
        <rdfs:subClassOf
rdf:resource="http://www.15926.org/rd/2005-11#STATUS"/>
    </rdfs:Class>

============================
AND NOW TO THE INDIVIDUALS
============================

<!--the happy marriage between John and Marry that started 24 March 1997 at
4:45pm UTC-->

    <owl:Thing rdf:ID="marriageBetweenJohnAndMary">
        <rdf:type rdf:resource="#HeterosexualMarriage"/>
        <ex:partner1 rdf:resource="#john-970324T1645Z"/>
        <ex:partner2 rdf:resource="#mary-970324T1645Z"/>
    </owl:Thing>

    <owl:Thing rdf:about="#marriageBetweenJohnAndMary">
        <rdf:type rdf:resource="#Happy"/>
    </owl:Thing>

<!--temporal part of John involved in the marriage-->

    <owl:Thing rdf:ID="john">
        <rdf:type rdf:resource="#Male"/>
    </owl:Thing>

    <owl:Thing rdf:ID="john-970324T1645Z">
        <rdf:type rdf:resource=" http://www.15926.org/rd/2005-11#MALE"/>
    </owl:Thing>

    <owl:Thing rdf:ID="temporalPartOfJohn-970324T1645Z">
        <rdf:type
rdf:resource="http://www.15926.org/rd/2005-11#TEMPORAL_COMPOSITION_WITH_DATE
_TIME"/>
        <ex:temporalPart rdf:resource="#john-970324T1645Z"/>
        <ex:temporalWhole rdf:resource="#john"/>
        <ex:validSince rdf:resource="#XSDT-970324T1645Z"/>
    </owl:Thing>

<!--temporal part of Mary involved in the marriage-->

    <owl:Thing rdf:ID="mary">
        <rdf:type rdf:resource="http://www.15926.org/rd/2005-11#FEMALE"/>
    </owl:Thing>

    <owl:Thing rdf:ID="mary-970324T1645Z">
        <rdf:type rdf:resource="http://www.15926.org/rd/2005-11#FEMALE"/>
    </owl:Thing>

    <owl:Thing rdf:ID="temporalPartOfMary-970324T1645Z">
        <rdf:type
rdf:resource=http://www.15926.org/rd/2005-11#TEMPORAL_COMPOSITION_WITH_DATE_
TIME/>
        <ex:part rdf:resource="#mary-970324T1645Z"/>
        <ex:whole rdf:resource="#mary"/>
        <ex:validSince rdf:resource="#XSDT-970324T1645Z"/>
    </owl:Thing>

<!--definition of date-time as an individual of the Class
XmlSchemaDateTime-->

    <owl:Thing rdf:ID="XSDT-970324T1645Z">
        <rdf:type
rdf:resource="http://www.15926.org/rd/2005-11#XML_SCHEMA_DATE_TIME"/>
        <dm:content
rdf:datatype="http://www.w3.org/2001/XMLSchema#datetime">1997-03-24T16:45Z</
dm:content>
    </owl:Thing>

============
[1] HYPERLINK
"http://www.tc184-sc4.org/wg3ndocs/wg3n1328/lifecycle_integration_schema.htm
l"http://www.tc184-sc4.org/wg3ndocs/wg3n1328/lifecycle_integration_schema.ht
ml

Regards,
Hans

____________________
Hans Teijgeler
ISO 15926 specialist
Netherlands
+31-72-509 2005
www.InfowebML.ws
hans.teijgeler@quicknet.nl

====================================================================

-----Original Message-----
From: semantic-web-request@w3.org [HYPERLINK
"mailto:semantic-web-request@w3.org"mailto:semantic-web-request@w3.org] On
Behalf Of Peter F. Patel-Schneider
Sent: Thursday, March 23, 2006 0:33
To: brian.mcbride@hp.com
Cc: larsga@ontopia.net; semantic-web@w3.org
Subject: Re: Interpretation of RDF reification


From: "McBride, Brian" <brian.mcbride@hp.com>
Subject: RE: Interpretation of RDF reification
Date: Wed, 22 Mar 2006 22:48:34 -0000


> > Ah, I see. This was very clear. So X represents a stating, and there
> > can be many statings of the same statement, in the sense that I
> > could state it today, and you may have stated it yesterday, giving
> > us two statings of one statement?
>
> Yes.
>
> >
> > > What do you intend to do with this "marriage relationship"?  To
> > > understand your use case, I'd like to know what sort of statements
> > > you'd like to make about the relatioship.
> >
> > Basically, the use case is to be able to state marriages as a single
> > triple (for convenience, say), while still retaining the ability to
> > talk about the marriage, and retaining the connection between the
> > triple and the marriage node.

Ah, well, this is *one* of the things that is lacking in the RDF account of
reification.  There is no connection between a reification and the triple it
reifies, and certainly no connection to an occurence (whatever "occurence"
might mean here) of the triple.

> I would need help from a logician like Peter or Pat on that one.
>
> Roughly, it would seem that there is the concept of the property,
> married, a relation which relates pairs of resource.
>
> Then there is the concept of Marriage which is a class.  For
> simplicity lets say there is a subclass of marriages, conventional
> marriages, Cmarriage, to allow for variations.  Cmarriages have a
> husband property and a wife property, a start date property and end
> date property and may have other properties.
>
> It seems like there should be some property that relates the class
> Married to the property married.  It would seem that husband and wife
> properties are distinguished in relation to Married and married from
> properties like startDate and endDate.

Well, if you want to go to FOL or an expressive ontology language you could
do most of this, but RDF hasn't anywhere near the expressive power required.

> I personal[l]y have not come across this before, but it feels like it
> should be a common pattern that ontologists would be familiar with.
> Maybe even a pattern that could be documented, as in the work of the
> OEP task force in SWBPD.

[...]

> Brian


peter

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