Re: [RDF-CONCEPTS] Skolemization

[I've been guilty of polluting -comments in this exchange - mea culpa.]

The point is that it is impossible for any implementation to guarantee that 
the IRI that they just minted is unique, and so it is impossible for any 
implementation to satisfy a *must* here.

peter

On 06/14/2013 08:30 AM, David Booth wrote:
> 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 15:39:48 UTC