Evaluating SKOS in Stardog

[Maatary Okouya]

I have build an database with the SKOS archetype. 

1 - I was wondering how the archetype is suppose to come. With some named graph containing skos or is it suppose to be invisible and assume to be there such owl, rdfs and etc...

Regarding the reasoning and constraints: 

1 - Where can i see the constraints that are actually to be enforced for skos ? (meaning what part of the spec is supported and what part is not)

2 - I have tried the following  

A skos:prefLabel "Aname"@en

When i run RDFS Plus OWL RL reasoning in TopBraid, i can see that:

 A rdfs:label "Aname"@en

is deducted. 

To me that sounds right given that it is only in OWL DL that we have annotation property,  that is, that skos:prefLabel and rdfs:label are actual annotation property. I understand that a DL reasoner should ignore that. However I have put the query reasoning Level to RDFS, and could not get that deduction.  

Moreover if i do 

select *

where 

{

  

  ?entity ?p ?o .

  ?p a rdf:Property .

 

}

I indeed get nothing.

Here is my small skos dataset:

:Author

  rdfs:subClassOf skos:Concept ;

  rdfs:subClassOf [

      rdf:type owl:Restriction ;

      owl:allValuesFrom :City ;

      owl:onProperty skos:related ;

    ] ;

  rdfs:subClassOf [

      rdf:type owl:Restriction ;

      owl:onProperty skos:related ;

      owl:someValuesFrom :City ;

    ] ;

  owl:disjointWith :City ;

.

:City

  rdfs:subClassOf skos:Concept ;

.

:CodeFor

  rdf:type owl:ObjectProperty ;

  rdfs:label "CodeFor"@en ;

  rdfs:subPropertyOf skos:related ;

.

:DC

  rdf:type :City ;

  skos:prefLabel "DC"@en ;

.

:Maatdeamon

  rdf:type :Author ;

  :CodeFor :DC ;

  skos:prefLabel "Daniel"@en ;

Finally, 

when i do : 

select (:DC as ?DC) ?p ?o

where {

:DC ?p ?o .

  ?p a owl:ObjectProperty

}

I get something really wierd: 

SPARQL Results

DC	p	o
http://iadb/skosTraning#DC	http://www.w3.org/2004/02/skos/core#related	http://iadb/skosTraning#Maatdeamon
http://iadb/skosTraning#DC		http://iadb/skosTraning#Maatdeamon

 I get that row with an empty property. Any idea of what that might be ?

So although skos:related is found out skos:semanticRelation is not exposed (probably that shall be expected ?)

 

[Maatary Okouya]

Does anyone has an idea at least on the RDFS reasoning problem that i have exposed below. That is, reasoning over Skos:PrefLabel. When using RDFS Reasoning why is it that stardog does not decude that if 

A skos:prefLabel "Aname"@en then A rdfs:label "Aname"@en ?

I would appreciate some explanation on that. 

As per the second problem, do you think it is a bug ?