[foaf-dev] beyond foaf:mbox_sha1sum

Gregory Williams greg at evilfunhouse.com
Sat Dec 19 22:19:26 CET 2009


On Dec 19, 2009, at 4:13 PM, Richard Cyganiak wrote:

> Hi Greg,
> 
> On 19 Dec 2009, at 19:44, Gregory Williams wrote:
> <snip>
>> I'm open to the idea that smushing can lead to unwanted results,
> 
> That's not just an idea, it's a well-documented phenomenon that multiple parties who have worked with FOAF crawls have encountered and documented.

I'm just trying to make the point that this seems to be reason to get the people emitting bad sha1sum triples to fix their code, not to scare people off of using sha1sum when it's legitimate.

>> but removing the IFP flag will clearly change the semantics involved and could dramatically affect the functioning of existing systems.
> 
> Evidence, please. Do you know of existing, deployed systems that use off-the-shelf OWL Full reasoners to make use of the built-in IFP semantics on foaf:mbox_sha1sum, and hence would be affected by the change?
> 
> The mere possibility of the existence of such systems doesn't make a compelling argument, I think.

Well, I can't speak for others but I've certainly got code that would break because smushing would stop working. It's not based on an "off-the-shelf OWL Full reasoner", but uses a fragment of OWL Full to support identity reasoning.

.greg



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