[Odrl-version2] Permissions and Prohibitions

[Susanne Guth]

Dear all!

This is really a tricky, difficult topic. For implementors anything that
does not follow the rules A1 and B1 is hard and leaves room for ambiguity.
I would like to add that Renato's rule E is one of the hardest:

> E) If A2 and B2 occurs, you can only do A2 and not B2

But what about the things that are not specified, are they allowed? or are
they forbidden? If we decide against A1 and B1 then we would need rule E
adapted, such as

 E-New) If A2 and B2 occurs, you can only do A2 and not B2, and everything
that is not specified is forbidden. Please note that the prohibition entity
is addressing requirement 1.7 
<http://www.odrl.net/2.0/WD-v2req-20050213.html>

Susanne

> 
> Dear all - an issue for discussion on if Permissions and Prohibitions
> can occur together (see the early model [1]) in the same expression.
> 
> A1) Permissions indicate the actions you are allowed to do *and* only 
> these actions
> B1) Prohibitions indicate the actions you are not allowed to do *but* 
> everything else is OK
> 
> If A1 and B1 are mutually exclusive, then it is OK.
> However, if you put them together in an expression, you need to refine 
> the rules, like:
> 
> A2) Permissions indicate the actions you are allowed to do
> B2) Prohibitions indicate the actions you are not allowed to do
> C) If A2 occurs and no B2, then you can only do A2
> D) If B2 occurs and no A2, then you can do anything except B2
> E) If A2 and B2 occurs, you can only do A2 and not B2
> 
> (Rule E is a bit redundant in that if you can only do A2, then that 
> also means
> you can't do B2)
> 
> An example of where Permissions and Prohibitions may be used together 
> is in
> the Creative Commons licenses. (In the ODRL CC Profile [2], we have 
> turned
> CC Prohibitions into negative Constraints.)
> 
> The issue is do we keep the Permissions and Prohibitions as mutually 
> exclusive
> or we have some refined rules and allow them both to appear in the same 
> expression.
> 
> Cheers
> 
> Renato Iannella
> ODRL Initiative
> http://odrl.net
> 
> [1] <http://odrl.net/2.0/images/odrl-V2-model-draft3.png>
> [2] <http://odrl.net/Profiles/CC/WD.html>
> 
> _______________________________________________
> ODRL-Version2 mailing list
> ODRL-Version2 at odrl.net
> http://lists.odrl.net/mailman/listinfo/odrl-version2
> 

-- 
Susanne Guth
susanne at odrl.net
ODRL Initiative
http://odrl.net/

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