W3C home > Mailing lists > Public > www-archive@w3.org > January 2004

Re: RDF Semantics: corrections(was: Re: RDF Semantics: two issues, connected to OWL)

From: pat hayes <phayes@ihmc.us>
Date: Thu, 15 Jan 2004 17:48:11 -0600
Message-Id: <p06001f0dbc2cd4ef18e6@[10.0.100.76]>
To: "Jos De_Roo" <jos.deroo@agfa.com>
Cc: www-archive@w3.org

>[Pat, I'm cc'ing www-archive as it's easier that way to point back]
>

OK <snip>

>  > Was there a particular question you had that I
>>  can focus on?
>
>Well, the backbround was an asking of your opinion
>about the last message of last year in www-archive
>http://lists.w3.org/Archives/Public/www-archive/2003Dec/0047.html
>Is there an aternative way of *proving* inconsistencies ??
>(our usage of log:inconsistentWith is what
>euler uses for the OWL test cases and also
>in some observer component that we test)

You asked there if this misuses anything. I don't think so.  All of 
these should logically be equivalent, but the exigencies of search 
might make some more effective than others:

A inconsistentWith B

(A and B) entails (false)

  where 'false' could be any explicit contradiction, in principle, but 
of course you would need a strongly complete system to be sure of 
getting every possible contradiction actually derivable, so should 
likely choose a single representative impossiblity-indicator such as 
(P and not P).

(A and B) entails not(A)

C: (A consistentWith B)
not C

Not sure if this is any help....

Pat

Oh, PS: proving inconsistencies. The only real technique is to derive 
an explicit contradiction, like the null clause in resolution. The 
'xml clash' thingie in RDFS was an example closer to home. You have 
to figure out the ways that inconsistencies can arise, in practice, 
and kind of nudge your search engine in those directions.


-- 
---------------------------------------------------------------------
IHMC	(850)434 8903 or (650)494 3973   home
40 South Alcaniz St.	(850)202 4416   office
Pensacola			(850)202 4440   fax
FL 32501			(850)291 0667    cell
phayes@ihmc.us       http://www.ihmc.us/users/phayes
Received on Thursday, 15 January 2004 18:48:13 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 7 November 2012 14:17:39 GMT