<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On May 3, 2011, at 9:00 PM, Steve Baskauf wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; ">But I was under the impression that one models things by describing classes and the properties that connect them.</span></blockquote><div><br></div><div>In OWL, properties connect instances, not classes. RDF allows metaclasses (things that are classes and instances), but doing this will throw most (all?) reasoners off the track.</div><br><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "> Classes are (to me) a very different thing than instances of classes. A model containing more than 13.6 million classes is at least 1.9 million times as complicated as a model with 7 classes.</span></blockquote><div><br></div><div>Yes and no. I can model a taxonomy as a subclass hierarchy of classes, or as a property-based (memberOf or some such) hierarchy of individuals that all instantiate a single "Taxon" class. The former isn't 1 million times more complex than the latter. However, they are not identical either, and which approach one chooses has significant consequences for how easy it is to express things about those taxa, and for inferring new things from those with a DL reasoner. </div><br><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "> I would hate to have to draw an RDF graph of that model</span></blockquote></div><div><br></div><div>I would as much hate to have to draw an RDF graph of 1.7 million instances. The point being, in order to draw a graph of how someone models a domain you don't draw a graph of the entire RDF triple store.</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>-hilmar</div><br><div> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><font class="Apple-style-span" face="Monaco" size="3"><span class="Apple-style-span" style="font-size: 11px; ">-- </span></font></div><div><font class="Apple-style-span" face="Monaco" size="3"><span class="Apple-style-span" style="font-size: 11px; ">===========================================================</span></font></div><div><font class="Apple-style-span" face="Monaco" size="3"><span class="Apple-style-span" style="font-size: 11px; ">: Hilmar Lapp -:- Durham, NC -:- informatics.nescent.org :</span></font></div><div><font class="Apple-style-span" face="Monaco" size="3"><span class="Apple-style-span" style="font-size: 11px; ">===========================================================</span></font></div><div><br class="webkit-block-placeholder"></div></div></span><br class="Apple-interchange-newline"> </div><br></body></html>