Re: shapes-ISSUE-91 (hsolbrig): Default Cardinality [SHACL Spec]

Odd. I was under the impression that "many" was an expressible 
cardinality concept in IT. You yourself represent it as "*".

However, my point, as I stated before, was about the interaction of 
cardinality and the "open/closed" assumption on the graph. 
"minCardinality=0" means that a property is optional. To me, this is not 
"unspecified" but conveys an actual meaning. Conceptually, optional 
properties are not the same as unnamed properties for the purposes of 
validation. I'll need to think this through more, and run through 
examples. There may be conditions that we have in current metadata 
validation that cannot be replicated in RDF validation.

kc

On 9/26/15 10:59 AM, Holger Knublauch wrote:
> Yes correct. No sh:maxCount triple means it is unlimited. This is
> consistent with how all other constraints work. The datatype of
> sh:maxCount is xsd:integer, so a "*" would not work. sh:maxCount=0 would
> mean that no triples are allowed.
>
> Holger
>
>
> On 9/26/15 4:19 PM, Karen Coyle wrote:
>> Holger, are you saying that currently there is no way to specify
>> maxCount = unlimited except to not include maxCount? Presumably either
>> "maxCardinality = *" or "maxCardinality = 0" would convey this.
>>
>> kc
>>
>> On 9/26/15 12:48 AM, Holger Knublauch wrote:
>>> Hypothetically, if we set the default of sh:maxCount to 1. How would one
>>> change it to unlimited?
>>>
>>> Holger
>>>
>>>
>>>
>>> On 9/25/15 10:15 PM, Karen Coyle wrote:
>>>> I think that the cardinality defaults interact with the closed/open
>>>> graph definition. If the graph is open, then a default of
>>>> "minCardinality = 0, maxCardinality = *" is pretty close to
>>>> meaningless. In an open graph, all potential predicates are "optional"
>>>> unless defined otherwise, and specifying optional predicates does not
>>>> invoke any useful behavior. In the case of an closed graph,
>>>> "minCardinality = 0" describes a specific optional predicate.
>>>>
>>>> SHACL, if I understand it correctly, describes an open graph by
>>>> default. This means that only ""minCardinality > 0" can be validated.
>>>>
>>>> Although the statement by Holger that "if something is left
>>>> unspecified then it should count as unconstrained" resonates, I would
>>>> consider the inclusion of a optional property to be specified, not
>>>> unspecified.
>>>>
>>>> kc
>>>>
>>>> On 9/25/15 1:02 AM, Holger Knublauch wrote:
>>>>> I believe if something is left unspecified then it should count as
>>>>> unconstrained. So if no sh:minCount or sh:maxCount is given then it
>>>>> should count as 0..* by default.
>>>>>
>>>>> PROPOSAL: Close ISSUE-91 stating that the default interpretations of
>>>>> sh:minCount and sh:maxCount (and their qualified counterparts) should
>>>>> remain as currently specified.
>>>>>
>>>>> Holger
>>>>>
>>>>> PS: A compact syntax may of course use different conventions and
>>>>> automatically generate the corresponding min/max triples.
>>>>>
>>>>>
>>>>> On 9/25/2015 0:46, RDF Data Shapes Working Group Issue Tracker wrote:
>>>>>> shapes-ISSUE-91 (hsolbrig): Default Cardinality [SHACL Spec]
>>>>>>
>>>>>> http://www.w3.org/2014/data-shapes/track/issues/91
>>>>>>
>>>>>> Raised by: Harold Solbrig
>>>>>> On product: SHACL Spec
>>>>>>
>>>>>> The defaults for cardinality in UML are [1..1]  (see:
>>>>>> MultiplicityElement.lowerBound() and MultiplicityElement.upperBound()
>>>>>> on page 41 of OMG specification ptc/2013-09-05).  Should these be the
>>>>>> defaults for mincount and maxcount in Section 3.1.5 of the SHACL
>>>>>> specification as well?  Currently they are [0..*].
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>>
>>
>
>
>

-- 
Karen Coyle
kcoyle@kcoyle.net http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet/+1-510-984-3600

Received on Saturday, 26 September 2015 13:25:49 UTC