Re: Apache Jena rules to find the minimum in a list of data property values

2021-12-05 Thread Luis Enrique Ramos García 
Hi dear,

The issue here is the monotonic level of owl, with sparql functions you can
get this information, but with owl based rules, or inference not (in a set
larger than 2).

The point is that to get that the reasoner (or function) should create a
list, order it and extract the first or last element of the list.


Luis

El dom, 5 dic 2021 a las 14:24, Jakub Jałowiec (<
j.jalow...@student.uw.edu.pl>) escribió:

> Thanks, that solves the problem and I'll stick to it for now.
> Nonetheless, is it possible to automatically infer being an instance of the
> hypothetical class "YoungestPerson" ("the person with the lowest foaf:age
> aggregate by house") in Apache Jena as described above? Ideally, I would
> prefer to separate my conceptual/declarative model from raw data
> manipulation using SPARQL. I am new to RDF & ontologies and I am not sure
> to what extent keeping those two is possible and if it is worth to actually
> invest a lot of time into that.
>
> Best regards,
> Jakub
>
> niedz., 5 gru 2021 o 10:12 Lorenz Buehmann <
> buehm...@informatik.uni-leipzig.de> napisał(a):
>
> > Hi,
> >
> >
> > the common pattern in SPARQL is to get the aggregated value in an inner
> > query first, then in the outer query get the entity with the aggregated
> > value:
> >
> > SELECT ?house ?person ?lowestAge {
> >?person foaf:age ?lowestAge .
> >?person covidepid:livesIn ?house .
> >
> >
> > {SELECT ?house (min(?age) as ?lowestAge)
> > WHERE {
> >?person foaf:age ?age .
> >?person covidepid:livesIn ?house .
> > }
> > GROUP BY ?house}
> > }
> >
> >
> >
> > On 03.12.21 02:16, Jakub Jałowiec wrote:
> > > Hi,
> > > I would appreciate any help with the following problem. I have a bunch
> of
> > > (foaf:Persons, myOntology:livesIn, myOntology:Place) triples. I am
> trying
> > > to find the youngest person in each myOntology:Place (i.e. the person
> > with
> > > the earliest value of foaf:age for each myOntology:Place).
> > > What I've tried so far were:
> > > - OWL complex classes (Class Expression Syntax (
> protegeproject.github.io
> > )
> > > ) -
> > per
> > > my understanding they have too weak expressivity to express aggregates
> > > among other individuals associated with them
> > > - SPARQL query - something along those lines would work fine but I do
> not
> > > know how to retrieve the IRI of the youngest person:
> > >
> > >> SELECT ?house (min(?age) as ?lowestAge)
> > >> WHERE {
> > >>?person foaf:age ?age .
> > >>?person covidepid:livesIn ?house .
> > >> }
> > >> GROUP BY ?house
> > >
> > > I am curious if extraction of the lowest foaf:age value among a group
> of
> > > people could be achieved using Apache Jena rules. From the
> documentation
> > (
> > > https://jena.apache.org/documentation/inference/#rules) it seems to me
> > that
> > > the closest it gets to it is to write my custom built-in function that
> > > would do exactly that. Is that correct?
> > >
> > > Best regards,
> > > Jakub
> > >
> >
>

Re: Apache Jena rules to find the minimum in a list of data property values

2021-12-05 Thread Martynas Jusevičius 
You could use the CONSTRUCT query form as rules and augment your model
with the constructed triples. Something like this (untested):

PREFIX  covidepid: <>
PREFIX  foaf: 

CONSTRUCT
  {
?person a covidepid:YoungestPerson .
  }
WHERE
  { SELECT  ?house ?person ?lowestAge
WHERE
  { ?person  foaf:age   ?lowestAge ;
 covidepid:livesIn  ?house
{ SELECT  ?house (MIN(?age) AS ?lowestAge)
  WHERE
{ ?person  foaf:age   ?age ;
   covidepid:livesIn  ?house
}
  GROUP BY ?house
}
  }
  }

Fix the covidepid: namespaces before use.
Execute using QueryExecution::execConstruct:
https://jena.apache.org/documentation/javadoc/arq/org/apache/jena/query/QueryExecution.html#execConstruct(org.apache.jena.rdf.model.Model)

On Sun, Dec 5, 2021 at 2:24 PM Jakub Jałowiec
 wrote:
>
> Thanks, that solves the problem and I'll stick to it for now.
> Nonetheless, is it possible to automatically infer being an instance of the
> hypothetical class "YoungestPerson" ("the person with the lowest foaf:age
> aggregate by house") in Apache Jena as described above? Ideally, I would
> prefer to separate my conceptual/declarative model from raw data
> manipulation using SPARQL. I am new to RDF & ontologies and I am not sure
> to what extent keeping those two is possible and if it is worth to actually
> invest a lot of time into that.
>
> Best regards,
> Jakub
>
> niedz., 5 gru 2021 o 10:12 Lorenz Buehmann <
> buehm...@informatik.uni-leipzig.de> napisał(a):
>
> > Hi,
> >
> >
> > the common pattern in SPARQL is to get the aggregated value in an inner
> > query first, then in the outer query get the entity with the aggregated
> > value:
> >
> > SELECT ?house ?person ?lowestAge {
> >?person foaf:age ?lowestAge .
> >?person covidepid:livesIn ?house .
> >
> >
> > {SELECT ?house (min(?age) as ?lowestAge)
> > WHERE {
> >?person foaf:age ?age .
> >?person covidepid:livesIn ?house .
> > }
> > GROUP BY ?house}
> > }
> >
> >
> >
> > On 03.12.21 02:16, Jakub Jałowiec wrote:
> > > Hi,
> > > I would appreciate any help with the following problem. I have a bunch of
> > > (foaf:Persons, myOntology:livesIn, myOntology:Place) triples. I am trying
> > > to find the youngest person in each myOntology:Place (i.e. the person
> > with
> > > the earliest value of foaf:age for each myOntology:Place).
> > > What I've tried so far were:
> > > - OWL complex classes (Class Expression Syntax (protegeproject.github.io
> > )
> > > ) -
> > per
> > > my understanding they have too weak expressivity to express aggregates
> > > among other individuals associated with them
> > > - SPARQL query - something along those lines would work fine but I do not
> > > know how to retrieve the IRI of the youngest person:
> > >
> > >> SELECT ?house (min(?age) as ?lowestAge)
> > >> WHERE {
> > >>?person foaf:age ?age .
> > >>?person covidepid:livesIn ?house .
> > >> }
> > >> GROUP BY ?house
> > >
> > > I am curious if extraction of the lowest foaf:age value among a group of
> > > people could be achieved using Apache Jena rules. From the documentation
> > (
> > > https://jena.apache.org/documentation/inference/#rules) it seems to me
> > that
> > > the closest it gets to it is to write my custom built-in function that
> > > would do exactly that. Is that correct?
> > >
> > > Best regards,
> > > Jakub
> > >
> >

Re: Apache Jena rules to find the minimum in a list of data property values

2021-12-05 Thread Jakub Jałowiec 
Thanks, that solves the problem and I'll stick to it for now.
Nonetheless, is it possible to automatically infer being an instance of the
hypothetical class "YoungestPerson" ("the person with the lowest foaf:age
aggregate by house") in Apache Jena as described above? Ideally, I would
prefer to separate my conceptual/declarative model from raw data
manipulation using SPARQL. I am new to RDF & ontologies and I am not sure
to what extent keeping those two is possible and if it is worth to actually
invest a lot of time into that.

Best regards,
Jakub

niedz., 5 gru 2021 o 10:12 Lorenz Buehmann <
buehm...@informatik.uni-leipzig.de> napisał(a):

> Hi,
>
>
> the common pattern in SPARQL is to get the aggregated value in an inner
> query first, then in the outer query get the entity with the aggregated
> value:
>
> SELECT ?house ?person ?lowestAge {
>?person foaf:age ?lowestAge .
>?person covidepid:livesIn ?house .
>
>
> {SELECT ?house (min(?age) as ?lowestAge)
> WHERE {
>?person foaf:age ?age .
>?person covidepid:livesIn ?house .
> }
> GROUP BY ?house}
> }
>
>
>
> On 03.12.21 02:16, Jakub Jałowiec wrote:
> > Hi,
> > I would appreciate any help with the following problem. I have a bunch of
> > (foaf:Persons, myOntology:livesIn, myOntology:Place) triples. I am trying
> > to find the youngest person in each myOntology:Place (i.e. the person
> with
> > the earliest value of foaf:age for each myOntology:Place).
> > What I've tried so far were:
> > - OWL complex classes (Class Expression Syntax (protegeproject.github.io
> )
> > ) -
> per
> > my understanding they have too weak expressivity to express aggregates
> > among other individuals associated with them
> > - SPARQL query - something along those lines would work fine but I do not
> > know how to retrieve the IRI of the youngest person:
> >
> >> SELECT ?house (min(?age) as ?lowestAge)
> >> WHERE {
> >>?person foaf:age ?age .
> >>?person covidepid:livesIn ?house .
> >> }
> >> GROUP BY ?house
> >
> > I am curious if extraction of the lowest foaf:age value among a group of
> > people could be achieved using Apache Jena rules. From the documentation
> (
> > https://jena.apache.org/documentation/inference/#rules) it seems to me
> that
> > the closest it gets to it is to write my custom built-in function that
> > would do exactly that. Is that correct?
> >
> > Best regards,
> > Jakub
> >
>

Re: Apache Jena rules to find the minimum in a list of data property values

2021-12-05 Thread Lorenz Buehmann 

Hi,


the common pattern in SPARQL is to get the aggregated value in an inner 
query first, then in the outer query get the entity with the aggregated 
value:


SELECT ?house ?person ?lowestAge {
  ?person foaf:age ?lowestAge .
  ?person covidepid:livesIn ?house .


{SELECT ?house (min(?age) as ?lowestAge)
WHERE {
  ?person foaf:age ?age .
  ?person covidepid:livesIn ?house .
}
GROUP BY ?house}
}



On 03.12.21 02:16, Jakub Jałowiec wrote:

Hi,
I would appreciate any help with the following problem. I have a bunch of
(foaf:Persons, myOntology:livesIn, myOntology:Place) triples. I am trying
to find the youngest person in each myOntology:Place (i.e. the person with
the earliest value of foaf:age for each myOntology:Place).
What I've tried so far were:
- OWL complex classes (Class Expression Syntax (protegeproject.github.io)
) - per
my understanding they have too weak expressivity to express aggregates
among other individuals associated with them
- SPARQL query - something along those lines would work fine but I do not
know how to retrieve the IRI of the youngest person:


SELECT ?house (min(?age) as ?lowestAge)
WHERE {
   ?person foaf:age ?age .
   ?person covidepid:livesIn ?house .
}
GROUP BY ?house


I am curious if extraction of the lowest foaf:age value among a group of
people could be achieved using Apache Jena rules. From the documentation (
https://jena.apache.org/documentation/inference/#rules) it seems to me that
the closest it gets to it is to write my custom built-in function that
would do exactly that. Is that correct?

Best regards,
Jakub

Apache Jena rules to find the minimum in a list of data property values

2021-12-02 Thread Jakub Jałowiec 
Hi,
I would appreciate any help with the following problem. I have a bunch of
(foaf:Persons, myOntology:livesIn, myOntology:Place) triples. I am trying
to find the youngest person in each myOntology:Place (i.e. the person with
the earliest value of foaf:age for each myOntology:Place).
What I've tried so far were:
- OWL complex classes (Class Expression Syntax (protegeproject.github.io)
) - per
my understanding they have too weak expressivity to express aggregates
among other individuals associated with them
- SPARQL query - something along those lines would work fine but I do not
know how to retrieve the IRI of the youngest person:

> SELECT ?house (min(?age) as ?lowestAge)
> WHERE {
>   ?person foaf:age ?age .
>   ?person covidepid:livesIn ?house .
> }
> GROUP BY ?house


I am curious if extraction of the lowest foaf:age value among a group of
people could be achieved using Apache Jena rules. From the documentation (
https://jena.apache.org/documentation/inference/#rules) it seems to me that
the closest it gets to it is to write my custom built-in function that
would do exactly that. Is that correct?

Best regards,
Jakub