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Re: [RDF-CONCEPTS] Skolemization

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 12 Jun 2013 10:02:40 -0500
Cc: David Booth <david@dbooth.org>, public-rdf-comments <public-rdf-comments@w3.org>
Message-Id: <FF38366A-8294-4003-ABE0-8B5DB133467B@ihmc.us>
To: Ivan Herman <ivan@w3.org>

On Jun 12, 2013, at 9:04 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?

I don't think it should , but I think I see David's point. Consider: **IF** you are planning to Skolemize, (Ie "do this") **THEN** you MUST, etc.. So its a conditional MUST.  Which does make a kind of sense, but IMO is way too subtle to put into normative prose as it will get misunderstood to be a simple MUST.

Skolemization is like overhearing someone use a word like "someone" and rephrasing what they said using a made-up name, John Doe 34 for the un-named person. And just like with "John Doe", it helps if you can recognize made-up names later. But if you happen to actually know who they are talking about (for some reason) then you could use the real name. You aren't OBLIGED to make up a name, but that is what you do when you can't (or don't want to) do any better. 

Pat

> 
> 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
>> 
> 
> -- 
> Ivan Herman, W3C
> Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> http://www.ivan-herman.net/foaf#me

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Received on Wednesday, 12 June 2013 15:03:09 UTC

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