<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 13 Apr 2012, at 24:29 , Norbert E. Fuchs wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"></blockquote><blockquote type="cite"><blockquote type="cite">On 12 Apr 2012, at 23:27 , David Whitten wrote:<br><br></blockquote></blockquote><blockquote type="cite"><div><blockquote type="cite">I tried the query:<br></blockquote><blockquote type="cite">Who is a woman and is not a human?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I got the answer:<br></blockquote><blockquote type="cite">Query cannot be answered.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I'm confused. Does RACE do queries that have negation?<br></blockquote><br>I guess that the query should be answered from the axioms given as example on RACE's web-site, i.e. <br><br>Every man is a human. Every woman is a human. Mary is a woman. John is a man.<br><br>RACE does answer queries containing negation, and the answer given is correct since the query cannot be deduced from the axioms. Maybe, you are confused by "Query cannot be answered." that perhaps should be replaced by "Query does not follow from axioms.".<font class="Apple-style-span" color="#007329"><br></font></div></blockquote><br></div><div>To shed more light on the situation, I replaced David's question "Who is a woman and is not a human?" by the theorem "There is a woman who is not a human." that – if we disregard the possible substitution of the query word "who" – generates the same proof. Here is the result</div><div><br></div><div><img height="188" width="1077" apple-width="yes" apple-height="yes" id="ff98c339-edd8-4d23-acc9-b1e9a5c00481" src="cid:400BACB1-9CF7-451A-92D0-820C0C4C2864@uzh.ch"></div><br><div>Here we get the unambiguous answer "Theorems do not follow from axioms." instead of the ambiguous "Query cannot be answered." that could be understood either as "Query does not follow from axioms." – which is intended – or as "RACE was not able do answer the query."</div><div><br></div><div>Regards.</div><div><br></div><div> --- nef </div></body></html>