Re: ISSUE-95: Proposed simplification and clean up of template mechanism

Irene,

I'll clarify.

Holger is proposing a model that involves meta-classes. I am proposing
a model that does not involve meta-classes.

Personally, I find models that use meta-classes to be harder to
understand than those that do not use meta-classes. Do you find models
the use meta-classes to be easier to understand?

-- Arthur



On Fri, Nov 13, 2015 at 12:02 PM, Irene Polikoff <irene@topquadrant.com> wrote:
> Arthur,
>
> I think it was Einstein who is credited with saying that "everything
> should be as simple as it can be, but not simpler.” As many, I find the
> statement insightful and agree with it. So, I think in principle we are in
> agreement on this, but then there is a matter of judgement and agreement
> over what different people consider to be as simple as it can be.
>
> As for DL, I don’t really know what it means in our context to “keep
> within bounds of DL”. I see DL as a pretty complex topic and don’t
> understand its relevance here. Are there applications for which DL is the
> simplest way to go and what are they? I don't have the definitive answer,
> but I doubt that data validation or UI description are it.
>
> If you are saying that for ease of understanding DL chosen not to have
> instance to also be a class and this precedence proves that such approach
> is "as simple as it can be, but not simpler”, I don’t quite follow the
> reasoning. First, I am not certain that ease of understanding was the
> motivation. As I heard it, this had to do with some limitations of tableau
> algorithms and concerns about decidability. Second, in trying to use OWL
> while staying (for whatever reason) within DL, many people found this
> separation too limiting for their modeling. They asked for it to be
> removed. Further work on the algorithms found that this limitation was not
> necessary and it was removed.
>
>
> Irene
>
>
>
>
>
> On 11/13/15, 7:54 AM, "Arthur Ryman" <arthur.ryman@gmail.com> wrote:
>
>>Irene,
>>
>>As a general rule, I think we should keep the SHACL model as simple as
>>possible to make life easier for our target users. I think we can keep
>>within the bounds of DL. What is your opinion?
>>
>>-- Arthur
>>
>>On Thu, Nov 12, 2015 at 2:44 PM, Irene Polikoff <irene@topquadrant.com>
>>wrote:
>>>
>>> Arthur,
>>>
>>> Prior to OWL 2, OWL DL indeed had a strict limitation regarding
>>> disjointness of classes and individuals, but this limitation was removed
>>> in OWL 2 even for DL. Users wanted to be able to have the same thing as
>>>a
>>> class and an individual and further work on the tableau algorithms for
>>>DL
>>> revealed that they can cope with this. At least, this is my
>>>understanding
>>> of where things stand today.
>>>
>>> Best,
>>>
>>> Irene Polikoff
>>>
>>>
>>>
>>>
>>> On 11/12/15, 2:24 PM, "Arthur Ryman" <arthur.ryman@gmail.com> wrote:
>>>
>>>>Irene,
>>>>
>>>>I am referring to OWL DL. The partitioning of things into classes,
>>>>properties, and individuals allows you to express description logics
>>>>in OWL. This is a restricted style of modelling which is simpler to
>>>>understand and makes certain computations more tractable.
>>>>
>>>>-- Arthur
>>>>
>>>>On Thu, Nov 12, 2015 at 2:07 PM, Irene Polikoff <irene@topquadrant.com>
>>>>wrote:
>>>>> I may have mentioned this before, but in case I didn¹t, I do not
>>>>>believe
>>>>> it is correct to say that the idea behind OWL is not to allow
>>>>>meta-classes
>>>>> and to have classes, properties and individuals to be disjoint.
>>>>>
>>>>> Irene Polikoff
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On 11/11/15, 11:24 PM, "Arthur Ryman" <arthur.ryman@gmail.com> wrote:
>>>>>
>>>>>>I feel that people have an easier time understanding models in which
>>>>>>meta-classes are absent. This is the idea behind OWL and description
>>>>>>logic in which things are either classes, properties, or individuals.
>>>>>
>>>>>
>>>
>>>
>
>

Received on Friday, 13 November 2015 18:30:31 UTC