- From: Pat Hayes <phayes@ihmc.us>
- Date: Tue, 1 Mar 2016 22:45:09 -0600
- To: Reto Gmür <reto@wymiwyg.com>
- Cc: David Booth <david@dbooth.org>, semantic-web@w3.org
On Feb 29, 2016, at 2:50 AM, Reto Gmür <reto@wymiwyg.com> wrote: > On Mon, Feb 29, 2016, at 03:04, David Booth wrote: >> On 02/26/2016 06:04 AM, Reto Gmür wrote: >>> Sure, still I think that schema:rangeIncludes is not meaningless (as it >>> restricts the rdfs:range statements that are possible) and that >> >> Under the standard open world assumption (OWA) I do not think it is >> correct to say schema:rangeIncludes *restricts* anything. Bear in mind >> that given the statement: >> >> :p schema:rangeIncludes :Cat . >> >> one could always add an arbitrary additional class to the property's >> "expected type(s)" by adding another statement like: >> >> :p schema:rangeIncludes :Dog . >> >> Therefore, the original statement cannot be *restricting* anything >> (under the OWA). > > I did not say that it restricts the possible values of the properties, > but I'm saying that it restricts the possible rdfs:range statements that > are possible without creating a contradiction. > >> >> Personally, I think a reasonable way to interpret its meaning is that it >> says 'there exists an individual :d such that :d rdf:type :Dog'. >> >>> it has >>> some pragmatic usefulness such as when building editors that suggest >>> values for a specific property. >> >> Agreed. And it's also useful if you're doing closed world reasoning. > > Well, even if you're closing the world I'm not sure you can do reasoning > about the instance data based on this property. > > I claim that for something to be expected it must be possible, based on > this one can create a contradiction with statements of necessity > expressed with rdfs:range. Nothing in the RDFS namespace can express anything about necessity. RDFS is not a modal logic. Pat Hayes > > However, I don't think that only what is expected is possible. So even > if we know that only :Cat and :Dog are expected the unexpected :Mouse is > still possible. > > Reto > > ------------------------------------------------------------ IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile (preferred) phayes@ihmc.us http://www.ihmc.us/users/phayes
Received on Wednesday, 2 March 2016 04:45:43 UTC