Is this ontology well formed?

Question

I'm trying to perform reasoners in this ontology. I post below the ontology.

    <?xml version="1.0"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
         xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
         xmlns:owl="http://www.w3.org/2002/07/owl#"
         xml:base="C:/Users/Rita/Desktop/parenthood.owl"
         xmlns="C:/Users/Rita/Desktop/parenthood.owl#">

<owl:Ontology rdf:about="C:/Users/Rita/Desktop/parenthood.owl"/>

<owl:ObjectProperty rdf:about="#has">
  <rdfs:domain rdf:resource="#Man"/>
  <rdfs:range rdf:resource="#Son"/>
</owl:ObjectProperty>

<owl:Class rdf:about="#Man">
  <rdfs:subClassOf rdf:resource="http://www.w3.org/2002/07/owl#Thing"/>
  <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">This is man</rdfs:comment>
</owl:Class>

<owl:Class rdf:about="#Woman">
  <rdfs:subClassOf rdf:resource="http://www.w3.org/2002/07/owl#Thing"/>
  <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">This is woman</rdfs:comment>
</owl:Class>

<owl:Class rdf:about="#Son">
  <rdfs:subClassOf rdf:resource="#Man"/>
  <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">This is son</rdfs:comment>
</owl:Class>

<owl:Class rdf:about="#Daughter">
  <rdfs:subClassOf rdf:resource="#Woman"/>
  <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">This is son</rdfs:comment>
</owl:Class>

<owl:Class rdf:about="#Father">
  <rdfs:subClassOf rdf:resource="#Man"/>
  <owl:equivalentClass>
    <owl:Class>
      <owl:intersectionOf rdf:parseType="Collection">
        <rdf:Description rdf:about="#Man"/>
        <owl:Class>
          <owl:unionOf rdf:parseType="Collection">
            <owl:Restriction>
              <owl:onProperty rdf:resource="#has"/>
              <owl:someValuesFrom rdf:resource="#Son"/>
            </owl:Restriction>
            <owl:Restriction>
              <owl:onProperty rdf:resource="#has"/>
              <owl:someValuesFrom rdf:resource="#Daughter"/>
            </owl:Restriction>
          </owl:unionOf>
        </owl:Class>
      </owl:intersectionOf>
    </owl:Class>
  </owl:equivalentClass>
  <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">This is father</rdfs:comment>
</owl:Class>

<Man rdf:about="#filippo">
  <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
  <has rdf:resource="#matteo"/>
</Man>

<Son rdf:about="#matteo">
  <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
</Son>


</rdf:RDF>

I expect the "filippo" individual to be assigned the class "father". is it right to expect that? or is the ontology bad formed? I used OWlAPI 5 and hermit as reasoner. I'm new in ontology field!! Please help. thanks, Rita

Answer 1

This answer is not exactly answering "is the ontology bad formed?", however, could give some directions towards how to check for ontological adequacies and prevent a common ontological problem known as the IS-A overloading problem using the OntoClean methodology Ref Ref Ref Ref.

A common problem while developing an ontology is the IS-A overloading problem. All ontologies are centered on a taxonomy, which is a hierarchy of classes (eg Father) and sub-classes (eg. Son). These classes and sub-classes can be instantiated with individuals (eg. Filippo individual assigned to the class Father, Matteo individual assigned to the class Son) and several individuals can be related using ObjectProperty (eg. Matteo hasFather Filippo) where hasFather is the ObjectProperty.

Meta-properties in OnoClean such as Rigidity and Identity can be used to describe the instanceOf relation towards developing a well-founded ontology.

Rigidity (+R): A property P is rigid if, for each x, P(x) is true in one possible world, then it is also true in all possible worlds. Person and location are rigid, while student and tall are not.

The instanceOf link between an individual and a rigid class is described by the term rigid in OntoClean.

Identity (+I): An identity criterion (IC) for a property is a binary relation Ip such that Px ^ Py ^ A Ip xy -> x=y. If, for a given property P, we are able to define such an Ip, then we say that P carries an IC for its instances.

By applying the meta-properties defined in Rigidity and Identity, it is expected to obtain a well-founded ontology which:

• Classify an entity as an instance of a Class
• Individuate an entity as a countably distinct instance of a Class