Re: atom link analysis - was: link confusion?

I am not going to reply your message in details. Just a note of my feeling 
that your first representation is simple, while the structured 
representations are complex. A simple representation favours searching, 
while a complex representation retards a search.


Jeremy

----- Original Message ----- 
From: "Henry Story" <henry.story@bblfish.net>
To: <atom-owl@googlegroups.com>; "'SWIG'" <semantic-web@w3.org>
Cc: "bloged" <users@bloged.dev.java.net>; "'Atom Syntax'" 
<atom-syntax@imc.org>
Sent: Tuesday, March 29, 2005 9:22 PM
Subject: atom link analysis - was: link confusion?


>
> I was trying to interpret the atom:link element [1]
>
> If I try to look at the spec in a simple relational way (what is being 
> related to what?)
> then, given the following example atom xml extract,
>
>   <entry>
>     ...
> <link href="http://bblfish.net/blog/page5.html#42"
>           type="text/html"
>           hreflang="en"
>           length="450"
>           title="The html entry"
>           rel="related/>
>    </entry>
>
> One may think of representing this with the following N3
>
> [ a :Entry;
>   :link [ :href <http://bblfish.net/blog/page5.html#42>;
>           :type "text/html";
>           :lang  "en";
>           :length "450";
>           :l_title  "The html entry"; # see note [2]
>           :rel    :alternative
>         ]
> ].
>
>
> The problem to my mind is that the above interpretation of the xml is 
> confusing
> relations that apply to the link (:rel, :l_title) and relations that apply
> to the object of the link (:type, :lang, :length).
>
> Hence I prefer the following
>
> @prefix arch: <http://sw.nokia.com/WebArch-1/>
> @prefix owl: <http://www.w3.org/2002/07/owl#>
>
> [ a :Entry;
>   :link [ :href [ owl:sameAs <http://bblfish.net/blog/page5.html#42>;
>                   arch:representation [
>                      :type "text/html";  # note [3]
>                                    :lang  "en";
>                                    :length "450"
>                                   ]
>                 ]
>           :l_title  "The html entry"; # see note [2]
>           :rel    :alternative
>         ]
> ].
>
>
> That seems quite good.
>
> Now the interesting thing is that from the above it would seem that one
> should be able to deduce the following:
>
> [ a :Entry;
>   :alternative [ owl:sameAs <http://bblfish.net/blog/page5.html#42>;
>                  arch:representation [
>                      :type "text/html";  # note [3]
>                                    :lang  "en";
>                                    :length "450"
>                                   ]
>                 ]
> ].
>
> Ie. the link object is not really an object, but as its name suggests
> is really a relation. This would not be such a problem except for the fact
> that we have now lost the title information that was placed on the link
> object.
>
> So perhaps what we have is that the link object is an anonymous 
> rdfs:SubPropertyOf
> the object of its :rel relation (in our example :alternative) which has a 
> special
> title attribute. That would allow us to make the above deduction I think.
>
> So if variable relations were allowed  (they may be in N3, I am not sure),
> one could write
>
> [ a :Entry;
>    _:link [ owl:sameAs <http://bblfish.net/blog/page5.html#42>;
>             arch:representation [
>                      :type "text/html";  # note [3]
>                                    :lang  "en";
>                                    :length "450"
>                                  ]
>          ]
> ].
> _:link :rel :alternative;
>        :l_title  "The html entry".
>
> where :rel is itself a rdfs:SubPropertyOf rdfs:SubProperty.
>
>
> This may make the atom link relation clearer to some :-)
>
>
> Henry Story
>
>
> [1] http://www.atompub.org/2005/03/12/draft-ietf-atompub-format-06.html
> [2] the title attribute of the link is called l_title to avoid confusing 
> it with the
>  title element of the entry
> [3] I am surprised the web arch ontology does not have the vocabulary for
>    :type, :lang and :length that atom has.
>
>
>
> On 25 Mar 2005, at 21:32, Henry Story wrote:
>> On 25 Mar 2005, at 17:36, Henry Story wrote:
>>> given the following example xml,
>>>
>>>   <entry>
>>>     ...
>>> <link href="http://bblfish.net/blog/page5.html#42"
>>>           type="text/html"
>>>           hreflang="en"
>>>           length="450"
>>>           title="The html entry"
>>>           rel="related/>
>>>    </entry>
>>> [snip]
>>> So a better interpretation of the initial xml would be the following
>>>
>>> _e1--is-a-> <Entry>
>>>  |--link-> _link
>>>           |--to---->_r--is-a-> <Representation>
>>>           |         |--href--> <http://bblfish.net/blog/page5.html#42>
>>>           |         |--type--> "text/html"
>>>           |         |--lang--> "en"
>>>           |         |-length-> 450
>>>           |-title--> "The html entry"
>>>           |--rel---> "related"
>>
>> Another interpretation of the original xml which would take into account 
>> the fact that
>> a link MUST have an href element would be:
>>
>> _e1--is-a-> <Entry>
>>  |--link-> _link
>>           |--href--><http://bblfish.net/blog/page5.html#42>
>>           |         |--representation-->_r
>>           |                             |--type--> "text/html"
>>           |                             |--lang--> "en"
>>           |                             |-length-> 450
>>           |-title--> "The html entry"
>>           |--rel---> "related"
>>
>>
>> which is saying that a link relates an entry and a resource, and that 
>> sometimes
>> it is appropriate to give extra information about representations of that 
>> resource.
>>
>> And so more it would perhaps be clearer for the xml to be stated like
>> this
>>
>> <entry>
>>     ...
>> <link title="The html Entry"
>>           rel="related"
>>           href="http://bblfish.net/blog/page5.html#42">
>> <representation        type="text/html"
>>             lang="en"
>>             length="450"/>
>>     </link>
>>  </entry>
>>
>> I am not saying that that is the answer, just that the it may help to 
>> make the
>> distinction clearer somehow between properties of the link and properties 
>> on the
>> object of the link.
>>
>> Henry
>>
>
>

Received on Wednesday, 30 March 2005 07:08:06 UTC