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Re: How to avoid that collections "break" relationships

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Sun, 30 Mar 2014 03:53:18 -0700
Message-ID: <5337F79E.6020202@gmail.com>
To: Pat Hayes <phayes@ihmc.us>, Markus Lanthaler <markus.lanthaler@gmx.net>
CC: public-hydra@w3.org, "'public-lod@w3.org' (public-lod@w3.org)" <public-lod@w3.org>, W3C Web Schemas Task Force <public-vocabs@w3.org>, Dan Brickley <danbri@danbri.org>

On 03/30/2014 12:13 AM, Pat Hayes wrote:
> On Mar 29, 2014, at 8:10 PM, Peter F. Patel-Schneider <pfpschneider@gmail.com> wrote:
>
>> On 03/29/2014 03:30 PM, Markus Lanthaler wrote:
>>> On Wednesday, March 26, 2014 5:26 AM, Pat Hayes wrote:
>>>> Hmm. I would be inclined to violate IRI opacity at this point and have
>>>> a convention that says that any schema.org property schema:ppp can have
>>>> a sister property called schema:pppList, for any character string ppp.
>>>> So you ought to check schema:knowsList when you are asked to look for
>>>> schema:knows. Then although there isn't a link in the conventional
>>>> sense, there is a computable route from schema:knows to
>>>> schema:knowsList, which as far as I am concerned amounts to a link.
>>> Schema.org doesn't suffer from this issue as much as other vocabularies do
>>> as it isn't defined with RDFS but uses its own, looser description
>>> mechanisms such as schema:domainIncludes and schema:rangeIncludes. So what
>>> I'm really looking for is a solution that would work in general, not just
>>> for some vocabularies.
>>> [...]
>>>
>>>
>>> --
>>> Markus Lanthaler
>>> @markuslanthaler
>>>
>> I would  like to see some firm definition of just how these looser description mechanisms actually work.
> Yes, I agree. Let me put the question rather more sharply. What follows from knowing that
>
> ppp schema:domainIncludes ccc . ?
>
> Suppose you know this and you also know that
>
> x ppp y .
>
> Can you infer x rdf:type ccc? I presume not, since the domain might include other stuff outside ccc. So, what *can* be inferred about the relationship between x and ccc ? As far as I can see, nothing can be inferred. If I am wrong, please enlighten me. But if I am right, what possible utility is there in even making a schema:domainIncludes assertion?
>
> If "inference" is too strong, let me weaken my question: what possible utility **in any way whatsoever** is provided by knowing that schema:domainIncludes holds between ppp and ccc? What software can do what with this, that it could not do as well without this?
>
> Having a piece of formalism which claims to be a 'weak' assertion becomes simply ludicrous when it is so weak that it carries no content at all. This bears the same relation to axiom writing that miming does to wrestling.
>
> Pat
>
>
Perhaps this could be somewhat sharpened to "that professional wrestling does 
to wrestling".

peter
Received on Sunday, 30 March 2014 10:53:48 UTC

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