A function to check the intances of OWLClass or OWLCLassExpression

[sapkotaruz11]

Is there a function which we can directly use to determine if an individual is an instance of a OWLClass or OWL-Class Expression? Something similar to isinstance function in python?

Example use case:

individual = OWLNamedIndividual(IRI('http://www.benchmark.org/family#','F2F36'))
parent = OWLClass(IRI('http://www.benchmark.org/family#','Parent'))
is_instance_of(individual, parent)

[Demirrr]

Yes indeed. For example, the following example is provided in the README.

from owlapy.owl_ontology_manager import OntologyManager
from owlapy.owl_reasoner import SyncReasoner
from owlapy.static_funcs import stopJVM

ontology_path = "KGs/Family/family-benchmark_rich_background.owl"
# Available OWL Reasoners: 'HermiT', 'Pellet', 'JFact', 'Openllet'
sync_reasoner = SyncReasoner(ontology = ontology_path, reasoner="Pellet")
onto = OntologyManager().load_ontology(ontology_path)
# Iterate over defined owl Classes in the signature
for i in onto.classes_in_signature():
    # Performing type inference with Pellet
    instances=sync_reasoner.instances(i,direct=False)
    print(f"Class:{i}\t Num instances:{len(instances)}")
stopJVM()

You just need to check whether individual is an element of sync_reasoner.instances(parent) .

We have also few more examples ,e.g.

1. Our doc finding instances
2. You can also find few examples in our tests (e.g. this one ).

[alkidbaci]

In addition to Demir's suggestion you can also check if the class assertion axiom for that individual + ce is entailed by the ontology axioms.

ontology_location = "../KGs/Family/family-benchmark_rich_background.owl"
reasoner = SyncReasoner(ontology_location)
individual = OWLNamedIndividual(IRI('http://www.benchmark.org/family#','F2F36'))
assertion_axiom = OWLClassAssertionAxiom(individual, OWLClass(IRI('http://www.benchmark.org/family#','Parent')))
is_entailed = reasoner.is_entailed(assertion_axiom)
print(is_entailed)

Keep in mind that SyncReasoner uses open world assumption and it may not entail an axiom that would otherwise be entailed in CWA. I suggest testing it with some complex class expressions before you continue with your experiments.