- From: Phil Dawes <pdawes@users.sourceforge.net>
- Date: Wed, 5 May 2004 07:23:32 +0100
- To: Benja Fallenstein <b.fallenstein@gmx.de>
- Cc: Phil Dawes <pdawes@users.sf.net>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, www-rdf-interest@w3.org
Benja Fallenstein writes: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Phil Dawes wrote: > | > > > | > > x:schnak rdfs:range aoeuii > | > > =====> > | > > x:schnak phil:rangeIncludes aoeuii > > Let's recapitulate: "There is a triple with property x:schnak and value > of type aoeuii" seemed an appropriate interpretation of the second > statement above. > > | Peter F. Patel-Schneider writes: > | > Perhaps, but this doesn't follow from the intuitive meaning that > you said > | > you were thinking of. Either the intuitive meaning or the > inference rule > | > are wrong. > | > | I'm not sure I understand. > > This is about the 'edge case' of empty sets. > > ~ x:schnak rdfs:range aoeuii > ~ "All triples with prop x:schnak have values of type aoeuii" > > ~ x:schnak phil:rangeIncludes aoeuii > ~ "There exist triples with prop x:schnak have values of type aoeuii" > > The first is true even if there are *no* triples with property x:schnak > at all. The second is not. That's why you cannot infer the second from > the first. Ah - I understand now - Many thanks, Phil
Received on Wednesday, 5 May 2004 06:34:34 UTC