Re: SHACL syntax and metamodel complexity

You mean it doesn't use SHACL syntax?  That was by design.

I could provide RDF encodings, using the current SHACL syntax where possible,
if that would help.

peter


On 02/27/2016 06:42 AM, Karen Coyle wrote:
> Thanks, Peter. So I find this intriguing but don't know what it means in
> actual SHACL terms since it doesn't use SHACL properties. Could you say what
> the changes would be?
> 
> kc
> 
> On 2/24/16 10:10 AM, Peter F. Patel-Schneider wrote:
>> More or less.
>>
>> "fillers of property p" = "those nodes that are the objects of s p o triples
>> for any particular unspecified s"
>>
>> It may be useful to also allow inverse properties and property paths so the
>> above rewrite would have to modified into something removed from actual
>> triples.
>>
>> peter
>>
>>
>> On 02/24/2016 09:53 AM, Karen Coyle wrote:
>>> "fillers" = "values"?
>>>
>>> On 2/24/16 9:03 AM, Peter F. Patel-Schneider wrote:
>>>> SHACL states property constraints in the following way
>>>>
>>>>     for the fillers of property ex:p
>>>>     the special fillers must all belong to class ex:s,
>>>>     there must be at least one,
>>>>     there must be at least five special fillers,
>>>>     they must all be either ex:a, ex:b, ex:c, ex:d, ex:e, ex:f, ex:d, ex:h,
>>>>       ex:i, or ex:j,
>>>>     there must be at most ten,
>>>>     the identifiers used for them must match regular expression r,
>>>>     they must all belong to class ex:c, and
>>>>     there must be at most seven special fillers.
>>>>
>>>> but not in the following way
>>>>
>>>>     for the fillers of property ex:p
>>>>     there must be at least one,
>>>>     they must all belong to class ex:c,
>>>>     there must be at most five,
>>>>     they must all belong to class ex:d, and
>>>>     there must be at least three.
>>>>
>>>> In my opinion, these features of the SHACL RDF syntax are contributing to
>>>> the complexity of the SHACL metamodel and to the number of decisions that
>>>> have to be made to construct the SHACL metamodel.
>>>>
>>>>
>>>> If SHACL stated constraints in the following way
>>>>
>>>>     there must be at least one filler of property ex:p,
>>>>     all the fillers of property ex:p must belong to class ex:c,
>>>>     there must be at most five fillers of property ex:p,
>>>>     all the fillers of property ex:p must belong to class ex:d, and
>>>>     there must be at least three fillers of property ex:p.
>>>>
>>>> then the the metamodel for SHACL constraints could have just particular
>>>> constraints (from the clauses above and other constraint constructs).  This
>>>> would be a significant simplification of the metamodel.
>>>>
>>>>
>>>> Even if SHACL permitted the second construction above and uniformly stated
>>>> multi-part particular constraints as at the end of the following there might
>>>> be significant simplifications of the metamodel
>>>>
>>>>     for the fillers of property ex:p
>>>>     there must be at least one,
>>>>     they must all be either ex:a, ex:b, ex:c, ex:d, ex:e, ex:f, ex:d, ex:h,
>>>>       ex:i, or ex:j,
>>>>     there must be at most ten,
>>>>     the identifiers used for them must match regular expression r,
>>>>     they must all belong to class ex:c, and
>>>>     there must be at between five and seven fillers that belong to class
>>>> ex:s.
>>>>
>>>>
>>>> These simplifications would require changes to the RDF syntax of SHACL.
>>>>
>>>> peter
>>>>
>>>>
>>>
>>
>

Received on Saturday, 27 February 2016 14:53:06 UTC