Re: blank nodes (once again)

On Wed, Mar 16, 2011 at 2:14 PM, Reto Bachmann-Gmuer
<> wrote:
> On Wed, Mar 16, 2011 at 5:34 PM, Pat Hayes <> wrote:
>> Quite. BTW, this would also be true if you had two graphs with URIs
>> instead of blank nodes, even if they were different URIs.
>> :joe :has [:dog1 a :dog]
>> :joe :has [:dog2 a :dog]
>> You would still not know that the two different *names* for dogs did or
>> did not name the same dog. Maybe (or maybe not)
>> :dog1 owl:sameAs :dog2
> Yet you would know something more about the world, that either :joe has two
> dogs or that :dog1 owl:sameAs :dog2. Of course, :joe might be a self-owned
> dog also known as :dog1 and :dog2.


How do you conclude this? As far as I can tell, given the RDF
semantics, all of these and more, were possibilities before you put
anything in a graph, and remain possible interpretations subsequently.

The whole part of this thread that tries to reason from "same
knowledge" to "same graph" seems the wrong kind of thinking. For one
thing it's hard to see this crowd seeing

G1: [a owl:Restriction; owl:onProperty :foo; owl:someValuesFrom owl:Thing]
G2: [a owl:Restriction; owl:onProperty :foo; owl:minCardinality 1]

as being the same graph, despite them having the same "knowledge"
according to the OWL semantics.


Received on Thursday, 17 March 2011 04:00:52 UTC