Re: [poe] Compatibility with common patterns for linking assets to policies

@simonstey my view on [2.7 Policy Rule Composition](https://w3c.github.io/poe/model/#composition)

First para (A Policy may contain ...) states "... each Rule may contain multiple Assets, Parties, Actions, Constraints, and Duties ..." but the [Rule](https://w3c.github.io/poe/model/#rule) definition talks only about "an Action/Asset" vs "one or more Parties/Constraints". This lets me conclude: only a single Action or Asset is allowed, but multiple Parties and Constraints.

But the ODRL specification appears to be different: the section about "create the atomic Rules" (further down in this 2.7 section and hidden between examples) is based on the view "each Rule may contain multiple Assets, Parties, Actions, Constraints, and Duties".
And it covers what @simonstey shows in the [Policy Inference](https://www.w3.org/2016/poe/wiki/Policy_Inference) document. 

This lower region of 2.7 also introduces Assets, Parties and Actions at the Policy level. These are shortcuts opening the expression of Asset(s), Party/ies and Actions of a Rule to two different ways. 
And the wording there is wrong: "This implies that these (Asset, Party, Action) classes are all common to all the Rules in the Policy,". No, they don't apply to any Duty Rule.
As said above, shortcuts may save come characters but makes processing a Policy harder - and I hope all Policy Architects will be aware that an Action at the Policy level applies to both permissions and prohibitions, a potential source of conflict.

These shortcuts may raise confusion as also Constraints may occur at the Policy level - but they do NOT apply to all Permission/Prohibitions of a Policy. In fact these Constraints are no shortcuts - what makes a distinction?

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The second para of 2.7 reminds of issue of #173: what is the "core" of ODRL? The IM [Introduction](https://w3c.github.io/poe/model/#intro) says "The information model covers the core concepts, entities and relationships that provide the foundational model for content usage statements." My conclusion: each word in the Information Model is about the core ODRL except words in non-normative sections - oops, the Introduction is non-normative.
Finally the second para tells: "This example shows the atomic level of a Policy where it is an irreducible Rule (that is, not able to be reduced or further simplified)". Based on what definitions or rules has Example 21 been formulated? Or is Example 21 the rule?



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Received on Thursday, 22 June 2017 14:28:57 UTC