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Re: Skolemization .well-known prefix: genid --> bnode or blanknode

From: Pat Hayes <phayes@ihmc.us>
Date: Thu, 19 Jul 2012 14:50:11 -0500
Cc: Gavin Carothers <gavin@carothers.name>, Gregg Kellogg <gregg@greggkellogg.net>, David Booth <david@dbooth.org>, Richard Cyganiak <richard@cyganiak.de>, public-rdf-comments <public-rdf-comments@w3.org>
Message-Id: <A7BE15AF-290B-44D1-B3C2-5BBC5B3C5484@ihmc.us>
To: nathan@webr3.org

On Jul 19, 2012, at 1:51 PM, Nathan wrote:

> Pat Hayes wrote:
>> On Jul 18, 2012, at 10:07 PM, Nathan wrote:
>>> Gavin Carothers wrote:
>>>> On Wed, Jul 18, 2012 at 7:05 PM, Gregg Kellogg <gregg@greggkellogg.net> wrote:
>>>>> On Jul 18, 2012, at 11:01 AM, David Booth wrote:
>>>>> Well, I wasn't a WG member when this was decided, but I did see it go by. IMO, the term "gemid" means nothing. To me, it says just "generated identifier", and nothing that would indicate that it denotes an unnamed resource (or existential identifier). My preference would be for something more like http://example.com/.well-known/anonid/d26a2d0e98334696f4ad70a677abc1f6, which provides a better linguistic clue as to what the IRI is intended to represent.
>>>> http://example.com/.well-known/existential/blahblah or perhaps
>>>> http://example.com/.well-known/∃/blahblah (lets break some bad IRI
>>>> implementations ;) )
>>>> Only half kidding. The name for the name for something that is
>>>> explicitly not a name or denotation is always going to be funky.
>> Sigh. The skolem name is not a name for the blank node, it is a name for the thing that exists, that the blank node asserts exists. This thing is just an ordinary thing. It might even have a name, for all we know, but this piece of RDF doesn't use that name. Just because some RDF uses a blank node to refer to it doesnt mark it out as special in any way, or as something that is inherently nameless. Someone delivered me a FedEx parcel yesterday. I have no idea what the name of the someone is, and I might use a bnode to describe my delivery in RDF, just as I use "someone" in English; but that isn't saying that the FedEx guy is a ghost or cannot be denoted. 
>>> "funky" is one way of putting it - weird thing is, outside of all the conversations about skolemization in the RDF WG, this seems like a ridiculously stupid idea that breaks about every principal of logic and web architecture and common sense.
>> Sorry you feel that way. As it was invented by (and named after) one the world's great logicians, and has been used by virtually every reasoning engine ever implemented for the last 40 years, and as it amounts, in this almost childishly simple RDF version, of nothing more than observing that one can make up a name to refer to something, and that this is OK provided you don't confuse things by re-using an old name, but instead really do generate a new name that hasnt been used before; because of all this, it seems pretty logical and normal to me. Don't you do this kind of thing all the time? Children do it spontaneously, without needing to be taught how. We do it, in effect., every time we use a definite noun phrase in English: "Joe's great-great-grandfather fought in the civil war." I don't know this old geezer's name, but I do have a way to refer to him, and I construct it on the fly as needed. What's funky about that? I might even go on to say "The Old Man was in the Uni
> on army"  and then we can have a conversation about ex:TheOldMan, and we have skolemized without even noticing that we did it. 
> Apologies Pat, I wasn't referring to skolemization itself, or it's presence in RDF - but rather the use of IRIs as skolem names,

Well, thats required by RDF syntax. I see no problem with it, myself. 

Pat



> specifically http(s) + .well-defined IRIs (URIs) - I personally feel it adds a layer of complexity that isn't needed when processing RDF (when you want to them back to bnodes) - but as I said ->
> 
>>> But then somehow all these clever people talking about it makes it seem rationale. I think.
> 
> Best,
> 
> Nathan
> 
> 

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Received on Thursday, 19 July 2012 19:50:47 UTC

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