I expect there will be many different engines which make those decisions differently. Check the documentation of software near you. Glossary These are not formal definitions - just phrases to help you get the hang of what these things mean. A bit of code for playing with this stuff, as grep is for regular expressions. Sucks in RDF in XML or N3, processes rules, and spits it out again.
Different engines have different sets fo rules.
Statement A subject, prediate and object which assert meaning defined by the particular prediate used. Thing In DAML, a generic name for anything - abstract, animate, inanimate, whatever. The class which anything is in. A particular property used to assert that a thing is in a certian Class. URI Universal Resource Identifier.