title: Unable to create DataPropertyAssertion with OWL API
body: <p>CODE:</p>
  
  <pre><code>OWLDataProperty prop = factory.getOWLDataProperty(IRI.create(getOntologyIRI()  + "#" +  owlDataProp));
  OWLNamedIndividual ind = factory.getOWLNamedIndividual(IRI.create(getOntologyIRI()  + "#" +  owlNamedIndividual));
  OWLLiteral lit = factory.getOWLLiteral(val);
  
  OWLDataPropertyAssertionAxiom axiom = factory.getOWLDataPropertyAssertionAxiom(prop, ind, lit);
  if(manager.addAxiom(this.ontology, axiom) == ChangeApplied.SUCCESSFULLY)
      return saveOntology();
  return false;
  </code></pre>
  
  <p>creates:</p>
  
  <p><a href="https://i.stack.imgur.com/gm3dz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gm3dz.png" alt="Protege SS"></a>
  and
  <a href="https://i.stack.imgur.com/XOTON.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XOTON.png" alt="enter image description here"></a></p>
  
  <p>But expected result is (manually created):</p>
  
  <p><a href="https://i.stack.imgur.com/yoJn0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yoJn0.png" alt="Protege SS2"></a></p>
  
  <p>I try to create OWLNegativeDataPropertyAssertionAxiom and it works fine. Also if I create getOWLNegativeDataPropertyAssertionAxiom first and then create OWLDataPropertyAssertionAxiom - it works.</p>
  
  <p>OWLAPI: <strong>owlapi-distribution-4.1.4.jar</strong></p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>Created ontologies:</p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  &lt;rdf:RDF xmlns="gunkoFB.owl#"
   xml:base="gunkoFB.owl"
   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
   xmlns:owl="http://www.w3.org/2002/07/owl#"
   xmlns:xml="http://www.w3.org/XML/1998/namespace"
   xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
   xmlns:gunkoFB="gunkoFB.owl#"
   xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"&gt;
  &lt;owl:Ontology rdf:about="gunkoFB.owl"/&gt;
  
  &lt;owl:DatatypeProperty rdf:about="gunkoFB.owl#hasFirstName"/&gt;
  
  &lt;owl:NamedIndividual rdf:about="gunkoFB.owl#Michal_Joštiak"&gt;
      &lt;hasFirstName rdf:datatype="http://www.w3.org/2001/XMLSchema#string"&gt;Michal&lt;/hasFirstName&gt;
  &lt;/owl:NamedIndividual&gt;
  </code></pre>
  
  <p></p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  
  &lt;rdf:RDF xmlns="gunkoFB.owl#"
   xml:base="gunkoFB.owl"
   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
   xmlns:owl="http://www.w3.org/2002/07/owl#"
   xmlns:xml="http://www.w3.org/XML/1998/namespace"
   xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
   xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"&gt;
  &lt;owl:Ontology rdf:about="gunkoFB.owl"/&gt;
  
  &lt;owl:DatatypeProperty rdf:about="gunkoFB.owl#hasFirstName"/&gt;
  
  &lt;owl:NamedIndividual rdf:about="gunkoFB.owl#Michal_Joštiak"/&gt;
  &lt;rdf:Description&gt;
      &lt;rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NegativePropertyAssertion"/&gt;
      &lt;owl:sourceIndividual rdf:resource="gunkoFB.owl#Michal_Joštiak"/&gt;
      &lt;owl:assertionProperty rdf:resource="gunkoFB.owl#hasFirstName"/&gt;
      &lt;owl:targetValue rdf:datatype="http://www.w3.org/2001/XMLSchema#string"&gt;Michal&lt;/owl:targetValue&gt;
  &lt;/rdf:Description&gt;
  </code></pre>
  
  <p></p>