What does it mean for permissions/prohibitions/duties if their constraint(s) are (un)satisfied?

[riannella]

TRACKER ISSUE-10: What does it mean for permissions/prohibitions/duties if their constraint(s) are (un)satisfied?

satisfiability of constraints

What does it mean for permissions/prohibitions/duties if their constraint(s) are (un)satisfied?

State:
RAISED
Product:
POE - Information Model
Raised by:
Simon Steyskal
Opened on:
2016-11-08
Description:
http://w3c.github.io/poe/model/#constraint states:

"[...] If multiple Constraint entities are linked to the same Permission, Prohibition, or Duty entity, then all of the Constraint entities MUST be satisfied. That is, all the Constraint entities are (boolean) anded. [...]"

Without actually explaining the concept of "satisfying a Constraint entity".

=> How can someone "satisfy a Constraint entity"?
=> What does it mean for permissions/prohibitions/duties if their constraints are unsatisfied?
=> Is a permission having an unsatisfied constraint equivalent to a prohibition? (and vice versa)
=> Should a permission/prohibition having an unsatisfied constraint simply be ignored? If so, is it possible for "ignored" perm/proh to become "active" again?

simon

[simonstey]

In the meantime, the section on constraints was reworked and quoted paragraph now reads as follows:

If multiple Constraint entities are linked to the same Permission, Prohibition, or Duty entity, then all the Constraint entities within the Rule MUST be satisfied. That is, all the Constraint entities are (boolean) anded together.

What is the Rule referring to? I suggest replacing Permission, Prohibition, or Duty entity with Rule and aligning the rest with:

• The Permission entity MAY refer to one or more constraints. The Permission becomes effective if all of the constraints are satisfied. [1]
• The Prohibition entity MAY refer to one or more constraints. The Prohibition becomes effective if all of the constraints are satisfied. [2]
• The Duty entity MAY refer to one or more constraints. The Duty becomes effective if all of the constraints are satisfied. [3]
  -> That's actually wrong.. A Duty is in effect from the very beginning, but the Permission a Duty is attached to isn't. Only if all constraints of a Duty are satisfied, is it considered to be fulfilled, and respective Permission may be in effect.

If the same Constraint is repeated within the same Rule, then these Constraints MUST be represented as a single Constraint entity using an appropriate operator value (for example, isAnyOf).

I'm not sure how isAnyOf could be used to achieve that as it is defined as [4]: "Indicating that a given value is any of the right operand of the Constraint."

Consider following example:

:p1 a odrl:Permission ;
	odrl:action odrl:distribute ;
	odrl:constraint :c1, :c1, :c2, :c3 . 

:c1 a odrl:Constraint ;
	odrl:leftOperand odrl:spatial ;
	odrl:operator odrl:eq ;
	odrl:rightOperand <http://ontologi.es/place/IT> .

:c2 a odrl:Constraint ;
	odrl:leftOperand odrl:spatial ;
	odrl:operator odrl:eq ;
	odrl:rightOperand <http://ontologi.es/place/IT> .

:c3 a odrl:Constraint ;
	odrl:leftOperand odrl:spatial ;
	odrl:operator odrl:eq ;
	odrl:rightOperand <http://ontologi.es/place/AUT> .

what constraints should be "merged" together and why are they considered to be the "same"?

[1] http://w3c.github.io/poe/model/#prohibition
[2] http://w3c.github.io/poe/model/#prohibition
[3] http://w3c.github.io/poe/model/#duty
[4] http://w3c.github.io/poe/vocab/#term-isAnyOf

[simonstey]

related #68

[riannella]

@simonstey I assume the first part of your comment above was just to replace "Permission, Prohibition, or Duty entity" with "Rule"?

[riannella]

I don't think we need the second part now on "same constraint" (I cannot remember why we added it...but there was a reason ;-)

I will remove that text.

[simonstey]

I assume the first part of your comment above was just to replace "Permission, Prohibition, or Duty entity" with "Rule"?

Kind of.. I suggest to replace:

If multiple Constraint entities are linked to the same Permission, Prohibition, or Duty entity, then all the Constraint entities within the Rule MUST be satisfied. That is, all the Constraint entities are (boolean) anded together.

with something along the lines of: "When multiple Constraints are attached to the same Rule they are interpreted as conjunction. A Rule becomes effective if all of its Constraints are satisfied."

I don't think we need the second part now on "same constraint" (I cannot remember why we added it...but there was a reason ;-)
I will remove that text.

+1

[riannella]

Done

[simonstey]

Done

The first part hasn't changed though..

[riannella]

Sorry, fixed now

[simonstey]

Section 3.6 Duty:

The Duty entity MAY refer to one or more constraints. The Duty becomes effective if all of the constraints are satisfied.

which means ->

{
   "@context": {
    "odrl": "http://www.w3.org/ns/odrl/2/"
    },
    "@type": "odrl:Offer",
    "@id": "http://example.com/policy:88",
    "permission": [{
        "assigner": "http://example.com/assigner:sony",
        "target": "http://example.com/music/1999.mp3",
        "action": "odrl:play",
        "duty": [{
            "action": "odrl:compensate",
            "constraint": [{
                "leftOperand": "odrl:payAmount",
                "operator": "odrl:eq",
                "rightOperand": "5.00",
                "unit": 
                  "https://www.currency-iso.org/dam/downloads/lists/list_one.xml#AUD"
            }],
            "constraint": [{
                "leftOperand": "odrl:event",
                "operator": "odrl:lt",
                "rightOperand": "odrl:policyUsage"
            }]
        }]
    }]
}  

as long as payamount != 5AUD, the duty is not in effect, hence the permission is granted

[riannella]

Hi @simonstey - i'm sorry but I don't follow the outcome.
Is it because of the word "effective"?

Would it be better to state "If all constraints of a Duty are satisfied, then the Duty is considered to be fulfilled".

[simonstey]

Is it because of the word "effective"?

Yes, see e.g. ->

effective (ɪˈfɛk tɪv) adj.

1. adequate to accomplish a purpose; producing the intended or expected result: effective teaching methods.
2. in operation or in force; functioning; operative: The law becomes effective at midnight.
3. producing a deep or vivid impression; striking: an effective photograph.
4. prepared and available for service, esp. military service.

Would it be better to state "If all constraints of a Duty are satisfied, then the Duty is considered to be fulfilled".

Yes.

1. A duty is in effect as long as its associated permission is "valid" (i.e., the permission's constraints are satisfied).
2. A duty is considered to be fulfilled if its constraints are satisfied.
3. For a permission to become effective, it must be valid and all of the permission's duties must be fulfilled.

[riannella]

Added 1) and 2) to Duty section and 3) to Permission section.

[riannella]

@simonstey Are you OK with this issue now?

[simonstey]

http://w3c.github.io/poe/model/#constraint still reads:

A Rule becomes effective if all of its Constraints are satisfied.

which is not the case for Duties

[riannella]

I will change that para to now read:

"If there are multiple Constraints applied to a Rule, then they are interpreted as conjunction in that each Constraint MUST be satisfied."

[riannella]

The last para of 3.6 Constraint section now reads:

"When multiple Constraints apply to the same Rule they are interpreted as conjunction. A Rule becomes effective if all of its Constraints are satisfied."

@simonstey ok?

[simonstey]

reopen due to #211

[riannella]

@simonstey Why is still unresolved here? That is not in #211 ?