Re: LDP agenda for 20 January - issue-92

On 20 Jan 2014, at 18:13, Arnaud Le Hors <lehors@us.ibm.com> wrote:

> I expected a few people to be missing but only four of us turned up for the first half hour so the official meeting didn't take place. 
> We used the time as an informal meeting, which a few others joined over time, to discuss some of the remaining issues. 
> No minutes were taken, today's meeting was basically canceled.

I came in late too, just in time to discuss Issue-92 [1] if I can summarise some of 
the arguments. 

1. the backup argument
======================

   The Backup argument made in support of issue 92 does not hold. Issue-92 says:

   [[
     By Alexandre's own example (making a backup of an LDPC/LDPR), the backup is just a document (it has the same RDF content, including the same rdf:type(s), but a different interaction model), not an LDPC or LDPR.
   ]]

  a) telling the truth
   -------------------

  There can be false statements made on the web, and if a document makes a false statement about a resource
  then that is a problem with the document, but since we rely on the final analysis on the headers the
  interactions can be done ok.

  In terms of truth the argument was made here:
    • http://lists.w3.org/Archives/Public/public-ldp-wg/2014Jan/0084.html
  The reliance on the header was voted as resolution of issue-91
    • http://www.w3.org/2012/ldp/track/issues/91


  b) How to make backups
  ----------------------

  The remaining argument Arnaud had was that this forces the 
  document to lie. If someone wants to make a backup and it is
  written 

    <> a ldp:Container .

  then the document is not telling the truth. There are in fact a
 number of answers on how to make backups.

  • change the mime type completely ( eg: text/plain ) and specify what 
   the mime type used to be
  • put the full text in an archiving format, something that says when
    the information was found, where it came from etc...
  • use N3 to do the previous with something like 
    
     { <> a ldp:Container } arch:meta [ 
               writtenBy <joe>;
               fetched "02-13-2013T00:00:00"^^xsd:dateTime;
               validUntil "02-14-2013T00:00:00"^^xsd:dateTime ] .
                                      
  • use an blank node for the container
  
    [] a ldp:Container;
      from "02-13-2013T00:00:00"^^xsd:dateTime;
      to "02-14-2013T00:00:00"^^xsd:dateTime .

  c) archiving argument is in a vicious spiral
   -------------------------------------------

  replacing the rdf:type with another relation - say ldp:interaction - would not help.
  Say we agree that it is better to write

  <> ldp:interaction ldp:Container .

  in the body of the document. Then the same problem would come up if one wanted to
  archive that document. Either <> acts like an LDPC or it does not. Luckily the previous
  two points show that the archiving problem is not a problem.


2. rel=profile
==============

the rel=profile spec is currently broken.
I made an argument for that and got support from Sandro Hawke here:

  http://lists.w3.org/Archives/Public/public-ldp-wg/2014Jan/0090.html

It is broken badly enough that minor tweaks cannot repair it. 
This shows that my -1 was completely justified, and so we are no longer
in a position to be able to assume the group is on a consensus behind
issue-92 with me as the only outcast. 

3. rel=interaction
==================

  If one were to create a new relation say rel=interaction which would
have an equivalent in rdf - call it ldp:interaction - then if is defined
in such a way that the following is true

ldp:Container  a owl:Class;
   owl:equivalentClass [ a owl:Restriction;
                 owl:hasValue ldp:Container;
                 owl:onProperty ldp:interaction ] .

then I can't object to it. But I'd just point out that 

  a) this requires a good definition of ldp:interaction and rel=interaction
    ( we can't write a blank cheque in advance of seeing what the text for 
    such a relation is going to be ). 

  b) it really is not clear what is gained by this, since there is an
    equivalence between ldp:Container and ldp:interaction as shown above
    and so rel=type would work as well.
 
Hope this helps,

	Henry


[1] https://www.w3.org/2012/ldp/track/issues/92

Received on Wednesday, 22 January 2014 10:32:04 UTC