[Pellet-users] Flat hierarchy

[Evren Sirin]

Hi,

I assume you are using the OWLAPI interface because the behavior you are 
seeing is due to OWLAPI which in turn relies on the upcoming OWL 1.1 
spec [1]. In OWL 1.1, typing triples are used only as hints to the 
parser and do not count for the declaration of entities (there is a 
specific way of declaring entities using owl11:declaredAs). And an 
entity that is not used in an axiom is ignored. Note that, adding just 
an annotation to the classes would be enough for them to be considered 
declared.

This specific feature of OWL 1.1 is still being debated (e.g. see latest 
discussions on the topic [2]) and it is not clear if this is how it will 
be in the final spec. Also Pellet Jena interface adopts a more 
backward-compatible approach and will consider typing triples enough for 
a declaration. So if you try the below example with Jena interface you 
would get your expected behavior.

Cheers,
Evren

[1] http://www.w3.org/2007/OWL/wiki/OWL_Working_Group
[2] http://lists.w3.org/Archives/Public/public-owl-wg/2008Mar/0165.html

On 3/16/08 9:59 AM, Georgios Meditskos wrote:
> Yes this is a solution.
> However my question is why Pellet does not infer this relationship, 
> since every class is subsumed by owl:Thing,
> according to OWL specifications.
>
> Pavel Klinov wrote:
>   
>> A simple workaround is to define your classes as subclasses of Thing.
>>
>> cheers,
>> --pavel
>>
>> Georgios Meditskos wrote:
>>     
>>> Hi all,
>>>
>>> is there any specific reason why Pellet does not take into account 
>>> flat hierarchies?
>>> For example, I you define a class, without any property, subclass or 
>>> superclass,
>>> the getClasses function returns an empty list.
>>> For example, for the following simple ontology
>>>
>>> <owl:Class rdf:ID="A" />
>>> <owl:Class rdf:ID="B" />
>>> <owl:Class rdf:ID="C" />
>>>
>>> Pellet does not create any class. However, in the following ontology, 
>>> the getClasses function returns the A and E classes.
>>>
>>> <owl:Class rdf:ID="A" />
>>> <owl:Class rdf:ID="B" />
>>> <owl:Class rdf:ID="C" />
>>> <owl:Class rdf:ID="E" >
>>>   <rdfs:subClassOf rdf:resource="#A" />
>>> </owl:Class>
>>>
>>> Thank you.
>>>
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