[oslc-core] Open Core issue cleanup: 6 (old 36) Ambiguity in Resource Shape definition + consequent questions

[John Arwe]

OPEN #36 Ambiguity in Resource Shape definition + consequent questions 
(JohnArwe 12/30/2011) 
Response Discussed at Jan 11 meeting. Proposal sent to list and response 
led to unclear statement if resolved.

Having reviewed this issue on the list [1], the email thread it spawned 
[2] after the meeting [3], it appears that all our energy was spent on Q1 
from the original email [4].  It is possible we agreed on the resolution 
for Q>1 on the call, but if we did so it was not recorded in minutes.  So 
I will recap the proposed changes here net of all the email thread 
improvements, and hopefully we can get consensus on tomorrow's call.

[5] Defines the Resource Shape resource definition.  It includes the 
following property definition:

> oslc:describes zero-or-many True Resource Reference n/a Type or types of 

resource described by this shape. 

Q1: This allows for multiple oslc:describes triples in a resource shape, 
but leaves open what the relationship is between these values and the 
(possibly multiple) rdf:type values in any given "described" resource 
instance (i.e. what condition(s) must be true in order for a given shape 
to describe a given resource instance appears to be under-specified). 
Breaking it down case by case, and stating what I *think* is the intent 
for each (looking for confirmation/disputes of this interpretation) with 
??? in cases where [1] really leaves me guessing.  I have implementation 
folks already interpreting the ??? cases differently, BTW. 

[3] clarified intent: Confirmation that the list of oslc:describes is 
intended to be the union of all rdfs:Class[es] the shape supports 

Proposed replacement text for oslc:describes description, from Arthur in 
[6]:

This shape describes resources that are of any of these types. Formally, a
shape S applies to a resource R if there is a triple R rdf:type T and 
there
is a triple S oslc:describes T.


As noted in [8], and confirmed in [3], It says nothing limiting, so 
oslc:instanceShape is simply orthogonal.





Q2-Q6, from [7] after the meeting in [3].

Since we agreed during the WG call that it is intentional and valid to 
have zero oslc:describes triples in a shape (so the shape describes only 
resources that explicitly link to it via a oslc:instanceShape  triple), 
here is a new (full replacement) proposal for the consequent editorial 
changes to [1]:

Q2: (editorial change) 
A Resource Shape describes the properties that are allowed or required 
by...
from: one         type               of resource . 
to:   one or more types or instances of resources. 
I'm not entirely happy with that (seems a bit awkward still), 
but I think it's accurate now so I claim 80-20 reached 
and give license to the editor(s) to improve it.

Q3: answered - 0 intentional, no change

Q4: Another disagreement between the words and oslc:describes cardinality 
providing a machine-readable definition...
from: of an          OSLC resource type              . 
to:   of one or more OSLC resource types or instances. 
FWIW: I kept "resource type" there, but "resource definition" might be 
more in keeping with the rest of the specs' content... did not do a wide 
search. 

Q5: (editorial nit) 
OSLC Creation Factory MAY provide ...
from: a Resource Shape  ... create a resource 
to:     Resource Shapes ... create   resources 
...and a similar change for Query Capability in the next sentence. 

Q6: (editorial nit) 
from: A Resource Shape resource can have a title and a        type . 
to:   A Resource Shape resource can have a title and a set of types. 



[1] http://open-services.net/wiki/core/OSLC-Core-V2-Issues/
[2] 
http://open-services.net/pipermail/oslc-core_open-services.net/2012-January/thread.html#1215
[3] http://open-services.net/bin/view/Main/OslcCoreMeetings20120111
[4] 
http://open-services.net/pipermail/oslc-core_open-services.net/2012-January/001204.html
[5] 
http://open-services.net/bin/view/Main/OSLCCoreSpecAppendixA?sortcol=table;table=up;up=#oslc_ResourceShape_Resource
[6] 
http://open-services.net/pipermail/oslc-core_open-services.net/2012-January/001210.html
[7] 
http://open-services.net/pipermail/oslc-core_open-services.net/2012-January/001208.html
[8] 
http://open-services.net/pipermail/oslc-core_open-services.net/2012-January/001215.html

Best Regards, John

Voice US 845-435-9470  BluePages
Tivoli OSLC Lead - Show me the Scenario
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