title: LUBM benchmark classes
body: <p>I have used <code>Lehigh University Benchmark</code> (LUBM) to test my application. <br/>
  What I know about <code>LUBM</code> is that its ontology contains 43 classes. <br/>
  But when I query over the classes I got 14 classes! <br/>
  Also, when I used Sesame workbench and check the "Types in Repository " section I got 14th classes which are: </p>
  
  <pre><code>AssistantProfessor 
  AssociateProfessor 
  Course 
  Department 
  Fullprofessor 
  GraduateCourse 
  GraduateStudent 
  Lecturer 
  Publication 
  ResearchAssistant
  ResearchGroup 
  TeachingAssistant 
  UndergraduateStudent 
  University 
  </code></pre>
  
  <p>Could any one explain to me the differences between them?</p>
  
  <p>Edit: Problem partially solved but now How can I retrieve RDF instances from the upper level of Ontology (e.g. Employee, book, Article, Chair, college, Director, PostDoc, JournalArticle ..etc) or let's say all 43 classes because I can just retrieve instances for the lower classes (14th classes) and the following picture for retrieving the instances from ub:Department </p>
  
  <p><img src="https://i.stack.imgur.com/dEANj.png" alt="enter image description here"></p>