I would like to better understand ontologies and reasoning. There is an interesting puzzle called Einstein's riddle on the net that can be solved with the help of ontologies and reasoning. I downloaded the OWL ontology from that site and imported it into Protege 4.0.2 (does not work with 4.1). I can start a reasoner by Reasoner → FaCT++, Reasoner → Classify…, but i don't know, how to visualize the individual results. How can I do this?
There are two ways in which you can visualise the results. Firstly, when you select the "Classes" Tab, you will see that there are two views available to you: the "Class hierarchy" view, which is the asserted taxonomy and the "Class Hierarchy View (inferred)", which is, as the name suggests, the inferred one. That gives you the class views. As Kaarel suggests, you can visualise the individuals reasoning in the Individuals tab.
Protege also allows you to add a number of other individuals views to the UI: make a new empty tab and then choose a view from the "Individuals View" sub-menue under the "Views" menue. Finally, you can use a number of external graphical tools to visualise: if you assert the inferred hierarchy and save it out to a file (in RDF-XML), you can then use tools such as Welkin, IsaViz etc. to get graphical representations.