<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV><DIV>On 27 Sep 2006, at 7:03 PM, Andre Meyer wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Corbel; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; ">Well, I agree with the reasoner part. But these are two separate things: an ontology enforcing the validity of triples in the store on the one hand and a reasoner that adds triples based on rules and ontological conclusions on the other hand. Does this make sense?<SPAN class="Apple-converted-space"> </SPAN><BR></SPAN></BLOCKQUOTE><DIV><BR class="khtml-block-placeholder"></DIV>No, it doesn't.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>In the case of the semantic web, ontologies and rules are used by reasoners and rule engines respectively to infer conclusions. These conclusions might be "Richard is a Person", or they might be "your store is inconsistent for X, Y, Z reasons". They will not say "you can't add this triple, it's invalid; People don't have wheels". Instead, your person is inferred to also be a car. It's up to you what you do with this information.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>You are thinking in terms of schemas in the XML sense. Disabuse yourself of this notion.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Ontologies do not enforce the validity of anything (at least, not in the sense in which you are thinking of 'enforcing').<BR><BR></DIV>You can try to do validation by making your store logically inconsistent:<DIV><BR class="khtml-block-placeholder"></DIV><DIV>Richard is a Person</DIV><DIV>Richard has a Wheel</DIV><DIV>Anything with Wheels is a Car</DIV><DIV>>>> People are disjoint from Cars <<< this is your attempt at validation.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>but it's hard to make this work.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>-R</DIV></BODY></HTML>