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Re: Explaining the benefits of http-range14 (was Re: [HTTP-range-14] Hyperthing: Semantic Web URI Validator (303, 301, 302, 307 and hash URIs) )

From: Leigh Dodds <leigh.dodds@talis.com>
Date: Fri, 21 Oct 2011 07:42:59 +0100
Message-ID: <CAJgK0KEzGg9bW7XEoSoRjNm8bLd=f92FHrCjocts9SS_1ZUQdw@mail.gmail.com>
To: Jonathan Rees <jar@creativecommons.org>
Cc: "public-lod@w3.org" <public-lod@w3.org>
Hi,

On 19 October 2011 23:10, Jonathan Rees <jar@creativecommons.org> wrote:
> On Wed, Oct 19, 2011 at 5:29 PM, Leigh Dodds <leigh.dodds@talis.com> wrote:
>> Hi Jonathan
>>
>> I think what I'm interested in is what problems might surface and
>> approaches for mitigating them.
>
> I'm sorry, the writeup was designed to do exactly that. In the example
> in the "conflict" section, a miscommunication (unsurfaced
> disagreement) leads to copyright infringement. Isn't that a problem?

Yes it is, and these are the issues I think that are worth teasing out.

I'm afraid though that I'll have to admit to not understanding your
specific example. There's no doubt some subtlety that I'm missing (and
a rotten head cold isn't helping). Can you humour me and expand a
little? The bit I'm struggling with is:

[[[
<http://example/x> xhv:license
       <http://creativecommons.org/licenses/by/3.0/>.

According to D2, this says that document X is licensed. According to
S2, this says that document Y is licensed
]]]

Taking the RDF data at face value, I don't see how the D2 and S2
interpretations differ. Both say that <http://example/x> has a
specific license. How could an S2 assuming client, assume that the
data is actually about another resource?

I looked at your specific examples, e.g. Flickr and Jamendo:

The RDFa extracted from the Flickr photo page does seem to be
ambiguous. I'm guessing the intent is to describe the license of the
photo and not the web page. But in that case, isn't the issue that
Flickr aren't being precise enough in the data they're returning?

The RDFa extracted from the Jamendo page including type information
(from the Open Graph Protocol) that says that the resource is an
album, and has a specific Creative Commons license. I think that's
what's intended isn't it?

Why does a client have to assume a specific stance (D2/S2). Why not
simply takes the data returned at face value? It's then up to the
publisher to be sure that they're making clear assertions.

> There is no heuristic that will tell you which of the two works is
> licensed in the stated way, since both interpretations are perfectly
> meaningful and useful.
>
> For mitigation in this case you only have a few options
> 1. precoordinate (via a "disambiguating" rule of some kind, any kind)
> 2. avoid using the URI inside <...> altogether - come up with distinct
> wads of RDF for the 2 documents
> 3. say locally what you think <...> means, effectively treating these
> URIs as blank nodes

Cheers,

L.

-- 
Leigh Dodds
Product Lead, Kasabi
Mobile: 07850 928381
http://kasabi.com
http://talis.com

Talis Systems Ltd
43 Temple Row
Birmingham
B2 5LS
Received on Friday, 21 October 2011 06:43:29 UTC

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