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Re: Property or class?

From: Diogo FC Patrao <djogopatrao@gmail.com>
Date: Mon, 1 Sep 2014 11:39:40 -0300
Message-ID: <CAFRj_AeHcMPAYFLB1GqTie0emFwEcFaQczVKWzgKOUKjkVju9w@mail.gmail.com>
To: "Eric Prud'hommeaux" <eric@w3.org>
Cc: Victor Porton <porton@narod.ru>, Hm Hrm <unixprog@googlemail.com>, "semantic-web@w3.org" <semantic-web@w3.org>
Hi Victor

I faced a similar problem years ago and went with "X a P"; in my case, X is
a patient instance and P a diagnosis. The alternative was "X :hasDiagnosis
P". Some thoughts:

*X a P*
Pro: P can be modelled as a Class, which is adequate (diagnostics can be
hierarchic), inference is fast
Con: If I have other classes attributed to X, and want to know the
subclasses related to diagnostic, It'll be more difficult (yet not
impossible)

*X :hasDiagnosis P*
Pro: easier to query when several different diagnosis (see Con above)
Con: I would need to create an instance for each diagnostic class (ie. flu
a Flu, patient1 :hasDiagnosis flu), or relate the instance directly to the
class (OWL-Full)

Years ago, I was modelling a similar case (precedence of data sources), and
found easier to work with comparative properties, such as:

db1 :isMoreTrustableThan db2

defining :isMoreTrustableThan as transitive, you can compare any instances
(given there's a path db1 :isMoreTrustableThan ...  :isMoreTrustableThan
dbn), however I couldn't get it to find the most trustable of all without
resorting to SPARQL.

Cheers,






--
diogo patrĂ£o




On Mon, Sep 1, 2014 at 10:05 AM, Eric Prud'hommeaux <eric@w3.org> wrote:

> * Victor Porton <porton@narod.ru> [2014-09-01 15:28+0300]
> > 01.09.2014, 10:07, "Hm Hrm" <unixprog@googlemail.com>:
> > > On 08/31/2014 06:43 PM, Victor Porton wrote:
> > >>  Suppose P is a precedence of operation X. Should I write "X a P ." or
> > >>  "X :precedence P ." (in Turtle format)?
> > >>
> > >>  What are (dis)advantages of both variants?
> > >
> > > Assuming that the property should link instance P to instance X, both
> of
> > > class :Operation, then you should use "X :precedence P".
> > >
> > > "X a P", a shortcut for "X rdf:type P", would imply that P is an
> > > rdf:Class and X an instance of said class P. Extending the semantics of
> > > 'rdf:type' and using an instance as a class seems a bad idea.
> >
> > P is a class (because I want rdf:subClassOf for properties.
> >
> > But I yet doubt whether an operation should be an instance of precedence.
>
> I wouldn't advise it, but you could always say that Addition is an
> instance of a thing with precedence 2 and Multiplication ... 6 (from
> <
> http://en.wikipedia.org/wiki/Operators_in_C_and_C%2B%2B#Arithmetic_operators
> >).
> My guess is that instead you want to model more like this:
>
>   :precedenceIncludes a owl:ObjectProperty .
>   :PrecedenceAtLeast1 a owl:Class .
>   :PrecedenceAtLeast2 rdfs:subClassOf a :PrecedenceAtLeast1 .
>   :PrecedenceAtLeast3 rdfs:subClassOf a :PrecedenceAtLeast2 .
>   # ...
>   :Operation a owl:Class;
>     rdfs:subClassOf [
>       owl:onProperty :precedenceIncludes ;
>       owl:someValuesFrom :PrecedenceAtLeast1
>     ] .
>   :Addition rdfs:subClassOf
>       :Operation ,
>       [ owl:onProperty :precedenceIncludes ;
>         owl:someValuesFrom :PrecedenceAtLeast2 ]
>   :Multiplication rdfs:subClassOf
>       :Operation ,
>       [ owl:onProperty :precedenceIncludes ;
>         owl:someValuesFrom :PrecedenceAtLeast6 ]
>
> That way you can apply the T-box to an A-box (e.g. a parse graph over
> which you are doing static analysis) and leverage inferences from the
> ontology.
>
> > --
> > Victor Porton - http://portonvictor.org
> >
>
> --
> -ericP
>
> office: +1.617.599.3509
> mobile: +33.6.80.80.35.59
>
> (eric@w3.org)
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Received on Monday, 1 September 2014 14:40:39 UTC

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