W3C home > Mailing lists > Public > www-rdf-logic@w3.org > April 2001

Re: Reification

From: David Allsopp <dallsopp@signal.dera.gov.uk>
Date: Mon, 09 Apr 2001 15:42:52 +0100
Message-ID: <3AD1CA6C.CFF6636E@signal.dera.gov.uk>
To: Danny Ayers <danny@panlanka.net>
CC: www-rdf-logic@w3.org

Danny Ayers wrote:

> <- Your scheme above is encoding, not expressing, because RDF has
> <- no mechanism
> <- that can be used to capture the meaning of negation.

> Why does it need to capture the meaning in any case - if machine A
> understands a = !b means 'not' and machine B understands a = !b means 'not'
> why does the data model have to understand for a message to be conveyed?

IANAL*, but I think it's because an arbitrary machine C, which only
knows 'standard' RDF, won't understand, and will not be able to process
the data in the way intended by A. The data then have different meanings
to different machines, which defeats the whole purpose of the semantic
web. The negation is not built-in to RDF, so it has no meaning in its
own right. The meaning is 'outside' the system, as in Pat Hayes'
"punched cards with writing on them".


David Allsopp.

*substituting Logician for the usual Lawyer. Proving whether this is an
improvement is left an an exercise for the reader. ;-)
/d{def}def/u{dup}d[0 -185 u 0 300 u]concat/q 5e-3 d/m{mul}d/z{A u m B u
m}d/r{rlineto}d/X -2 q 1{d/Y -2 q 2{d/A 0 d/B 0 d 64 -1 1{/f exch d/B
A/A z sub X add d B 2 m m Y add d z add 4 gt{exit}if/f 64 d}for f 64 div
setgray X Y moveto 0 q neg u 0 0 q u 0 r r r r fill/Y}for/X}for showpage
Received on Monday, 9 April 2001 10:46:54 UTC

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