title: Why is this DL-Query not returning any individuals?
body: <p>This DL-Query is not returning any individuals:</p>
  
  <ul>
  <li>Query (Protégé syntax) : <code>hasPet exactly 1 DomesticAnimal</code></li>
  </ul>
  
  <p>Here's part of the ontology:</p>
  
  <pre><code>:hasPet a           owl:ObjectProperty;
          rdfs:domain :Human;
          rdfs:range  :DomesticAnimal;
          owl:inverseOf : petOf;
  
  
  :Joe    a           :Human;
          hasPet      :Lassy.
  
  :Bob    a           :Human;
          hasPet      :Sparkey, Lucky.
  </code></pre>
  
  <p>Queries:</p>
  
  <ul>
  <li><code>petOf value Bob</code>  returns <code>Sparkey</code> and <code>Lucky</code></li>
  <li><code>petOf value Joe</code>  returns <code>Lassy</code></li>
  <li><code>hasPet exactly 1</code> returns nothing.</li>
  </ul>
  
  <p>Why isn't the last query returning <code>Joe</code>?
  I have tried it with in Protégé with Pellet, HermiT, and FaCT++, and it didn't work.</p>