W3C home > Mailing lists > Public > public-rdf-wg@w3.org > December 2011

Re: Naming the graph in the container. (Was: Re: [GRAPH] graph deadlock?)

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Fri, 23 Dec 2011 17:14:23 +0000
Message-ID: <4EF4B6EF.7010207@epimorphics.com>
To: Pat Hayes <phayes@ihmc.us>
CC: public-rdf-wg@w3.org


On 23/12/11 15:56, Pat Hayes wrote:
>
> On Dec 22, 2011, at 12:06 PM, Andy Seaborne wrote:
>
>>
>>
>> On 21/12/11 20:47, Jeremy Carroll wrote:
>>> On 12/21/2011 8:47 AM, Kingsley Idehen wrote:
>>>>> Jeremy: I am advocating that the IRI denotes the graph
>>>>>
>>>>>
>>>> Why not the Graph Container?
>>>
>>> In my mental model of the world, we take a URL like:
>>> http://www.w3.org/1999/02/22-rdf-syntax-ns
>>>
>>> when you do a get, and ask for content type application/rdf+xml
>>>
>>> you get an RDF/XML document that encodes a graph.
>>>
>>> To me, the RDF/XML document is the representation, and the graph
>>> is the resource.
>>
>> This isn't to be picky as such but to reflect the matter of being
>> precise and consistent. At RDF F2F2, we resolved:
>>
>> [[ In our documents, we'll use the terms "RDF Graph" for g-snap,
>> "Graph Container" for g-box, and "Graph Serialization" for g-text
>> ]]
>>
>> The resource is the "Graph Container" that can be poked with GET to
>> return the current state which is an RDF graph.
>>
>> The representation is the "Graph Serialization" that encodes that
>> RDF graph.
>
> Agreed about being precise with terminology. But I would like to push
> back on the implicit assumption here that the resource must be a
> graph container. Why can a URI not be a name for an RDF graph
> directly, not via HTTP GET of course, but simply a name *for the
> graph itself*? So an RDF graph can indeed be a resource, seems to me,
> at least if we acknowledge the possibility of attaching a name to one
> of them.

A resource [AWWW] can change state in general.  Not all resources do so 
but in the example Jeremy gave of 
<http://www.w3.org/1999/02/22-rdf-syntax-ns>, this happens to be a 
changeable resource by basic web, and
an unchanging resource ("should be") by extra convention.  If it's 
today's weather report, it changes.

Someone from W3C team can change the contents of 
http://www.w3.org/1999/02/22-rdf-syntax-ns.  Signing is a good example 
here.  What do you sign?  The result of the GET.

Our terminology resolution is for a "graph container" that yields a RDF 
Graph when poked by GET.

For an immutable "graph container", there is a 1-1 correspondence and 
the naming scheme could strip the indirection out.

> This was the idea of the original 'named graph' proposal, and there
> were reasons for this choice. In particular, we paid considerable
> attention to the idea of signing and authenticating secure RDF data.
> If I am putting my signature to some RDF content, I want it to be
> attached to the actual graph, not to a labile graph container that
> others can later modify.

This is what I was trying to point out.

"the graph is the resource" is not right when applied to a resource 
named by a http: URL without knowing something more and then you might 
want to record that fact by talking about the signed graph value.

 >>> I(<http://www.w3.org/1999/02/22-rdf-syntax-ns>) is that graph



We agreed "graph" ("RDF graph") is the mathematical value.
The contents of http://foo can be changed.

That's all I was saying.

> Failing this, I want to have secure, locked
> graph containers, but this is not a topic we have yet tackled. It is
> simpler and I think more conceptually correct to speak of naming the
> graph itself.
>
> Pat
>
>>
>> In the above text, "the graph is the resource" mixes things up a
>> little.  The resource is a Graph Container that can produce an RDF
>> Graph (a value; the container's state) on demand.
>>
>> I read
>>>>> I am advocating that the IRI denotes the graph
>> as
>>>>> I am advocating that the IRI denotes the RDF graph
>>
>> The "denotes a graph container" is a common, but different, usage
>> pattern.
>>
>> Andy
>>
>>
>
> ------------------------------------------------------------ IHMC
> (850)434 8903 or (650)494 3973 40 South Alcaniz St.
> (850)202 4416   office Pensacola                            (850)202
> 4440   fax FL 32502                              (850)291 0667
> mobile phayesAT-SIGNihmc.us       http://www.ihmc.us/users/phayes
>
>
>
>
>
Received on Friday, 23 December 2011 17:14:51 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:25:46 GMT