Re: 4.1.9 is obscure or too restrictive

On 12 Jan 2013, at 18:43, Alexandre Bertails <bertails@w3.org> wrote:

> On 01/12/2013 12:23 PM, Wilde, Erik wrote:
>> hello.
>> 
>> On 2013-01-12 16:06 , "Henry Story" <henry.story@bblfish.net> wrote:
>>> [[
>>> 4.1.9 LDPRs must use at least one RDF triple to represent a link
>>> (relationship) to another resource. In other words, having the source
>>> resource¹s URI as the subject and the target resource¹s URI as the object
>>> of the triple representing the link (relationship) is enough and does not
>>> require the creation of an intermediate link resource to describe the
>>> relationship.
>>> ]]
>>> https://dvcs.w3.org/hg/ldpwg/raw-file/default/ldp.html#general
>>> This seems to be saying more than that there should be at least 1 triple
>>> in an LDPR.
>>> It seems to be saying that there must be at least one triple where the
>>> subject or the object link to a different resource which are in different
>>> documents. Or it is trying to say that IF  links can be made to other
>>> resource they only require one triple.
>>> I really don't know. Any clarifications from the editors on the intention
>>> of this passage?
>> 
>> i guess this is primarily an indication of the general problem how to
>> separate LDP metadata (relevant for the data and interaction model) and
>> LDP content (opaque for the LDP protocol, but may contain anything
>> including LDP data). in XML, this can easily be done by defining a schema
>> and saying which parts matter for the data and interaction model, and
>> which parts are opaque payload (often then simply using wildcards for
>> those parts of the schema). i am wondering whether there are established
>> RDF design pattern to tackle this problem; i cannot really imagine that
>> we're the first ones having to deal with it.
> 
> TimBL and I had a discussion a few days ago about that.
> 
> Let's say that you're dereferencing the fragment-less URL X, and that
> you get back a header like this:
> 
> [[
> Link: <target>; rel=Y
> ]]
> 
> Then we could say that this is like having the triple
> 
> [[
> <> <http://w3.org/TO/BE/DETERMINED/Y> <target>
> ]]
> 
> This would be enough for us for linking WebACL-s resources (rel=acl)
> from <> at the protocol level, without messing with the actual
> data. LDP could have its own set of reserved URLs for its protocol.
> 
> Note that you can't have meta informations for hash-URIs this way. But
> this is actually ok -- and even a good thing -- as you want to state
> things about the resource document itself, not its content.

I am very much in favor of the spec having a section about the Link
relation explaining something such as the above, with perhaps a number
of relations to consider such as acl and meta.

meta would be very important I suppose for binary content....


> 
> Alexandre.
> 
>> 
>> thanks and cheers,
>> 
>> dret.
>> 
>> 
>> 
> 

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