Why is HermiT or Pellet Reasoner for Protegev5.5 is not detecting inconsistency in Ontology

Question

I have used an object property O to relate Class A with Class B. I also have instance a and b of classes A and B respectively. I have used the same object property O to relate the instances a and b.

Again, I have used the same object property O to link a with c, where c is an instance of Class C which is not linked with class A or B using any object property. Reasoners are still showing that the Ontology is Consistent. My question is "Should this not be marked as inconsistent by the reasoners? Please enlighten me regarding your answer, whether the answer is 'Yes' or 'No' and the reason behind your answer"?

Thanks in advance.

Answer 1

You understand the semantics of domain and range axioms incorrectly. In the case of your object property O it merely states that whenever 2 individuals x, y are linked via O it means that the reasoner will infer that x is of type A and y is of type B.

In the case linking individuals a and c where c is of type C you will notice that c is also now inferred to be of type B.

If you want to see an inconsistency, what you can do is make classes B and C disjoint. Then linking a and c via O will result in an inconsistency.

BTW, if you are interested, on my blog I write about OWL2 ontologies and the use of reasoners and some of the counter intuitive ways in which reasoners can seem to "fail".