W3C home > Mailing lists > Public > public-rdf-comments@w3.org > June 2013

Re: [RDF-CONCEPTS] Skolemization

From: David Booth <david@dbooth.org>
Date: Fri, 14 Jun 2013 11:30:27 -0400
Message-ID: <51BB3713.1010108@dbooth.org>
To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
CC: Ivan Herman <ivan@w3.org>, public-rdf-comments <public-rdf-comments@w3.org>
that isn't the point.  the point is that the burden is on the 
implementer to avoid minting a URI that is already in use.  do you want 
to get into all of the details of explaining how distributed URI 
allocation works,  to avoid URI squatting?  I certainly don't.

David


On 06/13/2013 02:43 AM, Peter F. Patel-Schneider wrote:
> How can any system be entirely sure that any IRI it mints for
> skolemization *is* globally unique?  If this is not possible, and I fail
> to see how it can be possible, then no system could ever do
> skolemization under the *must* wording.
>
> peter
>
> On 06/12/2013 08:53 AM, David Booth wrote:
>> On 06/12/2013 10:04 AM, Ivan Herman wrote:
>>>
>>>
>>> David Booth wrote:
>>>> I'd like to propose a small change in section on Skolemization:
>>>> https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html#section-skolemization
>>>>
>>>>
>>>>
>>>> Regarding: "Systems wishing to do this SHOULD mint a new, globally
>>>> unique IRI (a
>>>> Skolem IRI) for each blank node so replaced." it seems to me that this
>>>> conformance requirement should be a MUST -- not a SHOULD -- because
>>>> the system
>>>> has already made the free choice to skolemize.
>>>
>>> I do not follow this. Why should be a MUST?
>>
>> Because an IRI that is not globally unique would not be logically
>> equivalent to a bnode, and thus could significantly change the
>> semantics, and that would violate the intent of skolemization.  If it
>> were a SHOULD then
>>
>>   _:b :foo :bar .
>>
>> could be changed to
>>
>>   :bar :foo :bar .
>>
>> If someone makes a change like that they should not be able to claim
>> that the change was conformant to the RDF spec.
>>
>> Bear in mind that the decision to perform the skolemization is still
>> optional -- it's a MAY.  The MUST only kicks in after they have made
>> that choice: if they choose to do it they MUST do it properly.
>>
>> David
>>
>>>
>>> Ivan
>>>
>>>
>>>>
>>>> Specific wording changes that I suggest:
>>>>
>>>> 1. Change:
>>>>
>>>>      "Systems wishing to do this SHOULD mint a new, globally
>>>>      unique IRI (a Skolem IRI) for each blank node so replaced."
>>>>
>>>> to:
>>>>
>>>>      "Systems choosing to do this MUST mint a new, globally
>>>>      unique IRI (a Skolem IRI) for each blank node so replaced.
>>>>      Each such Skolem IRI SHOULD conform to the syntactic
>>>>      requirement for a well-known IRI [WELL-KNOWN] with the
>>>>      registered name genid. This is an IRI that uses the HTTP or
>>>>      HTTPS scheme, or another scheme that has been specified to
>>>>      use well-known IRIs; and whose path component starts with
>>>>      /.well-known/genid/."
>>>>
>>>> 2. Delete the paragraph:
>>>> [[
>>>> Systems that want Skolem IRIs to be recognizable outside of the system
>>>> boundaries should use a well-known IRI [WELL-KNOWN] with the
>>>> registered name
>>>> genid. This is an IRI that uses the HTTP or HTTPS scheme, or another
>>>> scheme that
>>>> has been specified to use well-known IRIs; and whose path component
>>>> starts with
>>>> /.well-known/genid/.
>>>> ]]
>>>>
>>>> Thanks,
>>>> David
>>>>
>>>
>>
>
>
>
>
Received on Friday, 14 June 2013 15:30:55 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 20:29:57 UTC