owlprotegeinferencereasoner

OWL Equivalent Classes as complement of Sibling SubClass

I have the following made up example class hierarchy for clearing my doubt.

Example Class Hierarchy

The class of Dog and Human are subclasses of Animal. Also present is the class Leash.

I have modelled the Dog class as a Defined Class with a property restriction on an object property wearsLeash as shown.

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I have modelled the Human class as the complement of the Dog class as shown

enter image description here

I have three individuals for these classes as below. Leo is supposed to be the Dog and David the Human

enter image description here

I have asserted that Leo wearsLeash RedLeash as shown.

enter image description here

On running the built-in reasoner, Leo gets classified as a Dog but David doesn't get classified as a Human. My questions is why is it that David not inferred as an individual of Human as the class of animals that are not dogs? Is it due to the Open world assumption ? What other ways do I have to automatically infer David as Human using this logic?

Thanks!

EDIT: OWL file

@prefix : <http://www.semanticweb.org/university/untitled-ontology-107#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix xml: <http://www.w3.org/XML/1998/namespace> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@base <http://www.semanticweb.org/university/untitled-ontology-107> .

<http://www.semanticweb.org/university/untitled-ontology-107> rdf:type owl:Ontology .

#################################################################
#    Object Properties
#################################################################

###  http://www.semanticweb.org/university/untitled-ontology-107#wearsLeash
:wearsLeash rdf:type owl:ObjectProperty .


#################################################################
#    Classes
#################################################################

###  http://www.semanticweb.org/university/untitled-ontology-107#Animal
:Animal rdf:type owl:Class .


###  http://www.semanticweb.org/university/untitled-ontology-107#Dog
:Dog rdf:type owl:Class ;
     owl:equivalentClass [ owl:intersectionOf ( :Animal
                                                [ rdf:type owl:Restriction ;
                                                  owl:onProperty :wearsLeash ;
                                                  owl:someValuesFrom :Leash
                                                ]
                                              ) ;
                           rdf:type owl:Class
                         ] ;
     rdfs:subClassOf :Animal ;
     owl:disjointWith :Human .


###  http://www.semanticweb.org/university/untitled-ontology-107#Human
:Human rdf:type owl:Class ;
       owl:equivalentClass [ owl:intersectionOf ( :Animal
                                                  [ rdf:type owl:Class ;
                                                    owl:complementOf :Dog
                                                  ]
                                                ) ;
                             rdf:type owl:Class
                           ] .


###  http://www.semanticweb.org/university/untitled-ontology-107#Leash
:Leash rdf:type owl:Class .


#################################################################
#    Individuals
#################################################################

###  http://www.semanticweb.org/university/untitled-ontology-107#David
:David rdf:type owl:NamedIndividual ,
                :Animal .


###  http://www.semanticweb.org/university/untitled-ontology-107#Leo
:Leo rdf:type owl:NamedIndividual ,
              :Animal ;
     :wearsLeash :RedLeash .


###  http://www.semanticweb.org/university/untitled-ontology-107#RedLeash
:RedLeash rdf:type owl:NamedIndividual ,
                   :Leash .


#################################################################
#    General axioms
#################################################################

[ rdf:type owl:AllDifferent ;
  owl:distinctMembers ( :David
                        :Leo
                      )
] .


###  Generated by the OWL API (version 4.5.9.2019-02-01T07:24:44Z) https://github.com/owlcs/owlapi
Solution

  • In the ontology Human is defined as the intersection of Animal and the complement of Dog, which, for the purpose of classifying Human instances, is equivalent to defining Animal as the disjoint union of Dog and Human.

    This means that anything that is defined as being an Animal will be either a Dog or a Human; an instance can be classified as a Dog if it is known to wear a leash.

    The problem here is that David is not known to wear a leash and is not known not to wear a leash; Open World Assumption means that the reasoner cannot choose either possibility and cannot, therefore decide whether David is a Dog or a Human. To obtain what you want it's necessary to add more information to the ontology, such as that David belongs to a class that is outside the domain of wearsLeash.