W3C home > Mailing lists > Public > semantic-web@w3.org > March 2011

Re: a blank node issue

From: Sandro Hawke <sandro@w3.org>
Date: Wed, 02 Mar 2011 13:37:41 -0500
To: Pat Hayes <phayes@ihmc.us>
Cc: Richard Cyganiak <richard@cyganiak.de>, William Waites <ww@styx.org>, nathan@webr3.org, Ivan Shmakov <oneingray@gmail.com>, semantic-web@w3.org
Message-ID: <1299091061.2169.174.camel@waldron>
On Wed, 2011-03-02 at 12:21 -0600, Pat Hayes wrote:
> On Mar 2, 2011, at 9:54 AM, Richard Cyganiak wrote:
> 
> > On 2 Mar 2011, at 14:18, William Waites wrote:
> >> maybe some convention or
> >> standard for skolemising blank nodes so they can be 
> >> referred to might be a good thing?
> > 
> > There is already a convention/standard for skolemising blank nodes: just use a URI instead.
> 
> But that subtly changes the RDF, because the URI has global scope. 

I understood Richard to be speaking somewhat tongue-in-cheek, saying
that people should just never use blank nodes.

I agree that *software* should not change blank nodes to nodes with a
URI label.  But, when practical, *people* probably should, as they are
authoring.

In general, blank nodes are a convenience for the content provider and a
burden on the content consumer.   Higher quality data feeds use fewer
blank nodes, or none.   Instead, they have a clear concept of identity
and service for every entity in their data.

If someone in the middle tries to convert (Skolemize) blank nodes, it's
a large burden on them. Specifically, they should provide web service
for those new URIs, and if they get updated data from their sources,
they're going to have a very hard [perhaps impossible] time
understanding what really changed.

   -- Sandro

> Pat
> 
> > 
> > Richard
> > 
> > 
> >> 
> >> Cheers,
> >> -w
> >> -- 
> >> William Waites                <mailto:ww@styx.org>
> >> http://river.styx.org/ww/        <sip:ww@styx.org>
> >> F4B3 39BF E775 CF42 0BAB  3DF0 BE40 A6DF B06F FD45
> >> 
> > 
> > 
> 
> ------------------------------------------------------------
> IHMC                                     (850)434 8903 or (650)494 3973   
> 40 South Alcaniz St.           (850)202 4416   office
> Pensacola                            (850)202 4440   fax
> FL 32502                              (850)291 0667   mobile
> phayesAT-SIGNihmc.us       http://www.ihmc.us/users/phayes
> 
> 
> 
> 
> 
> 
> 
Received on Wednesday, 2 March 2011 18:38:01 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 21:45:41 GMT