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Re: Thing and Class

From: Jie Bao <baojie@cs.rpi.edu>
Date: Wed, 27 Aug 2008 21:24:05 -0400
Message-ID: <b6b357670808271824j639db986j582a4e616502c9ab@mail.gmail.com>
To: "Richard H. McCullough" <rhm@pioneerca.com>
Cc: "Harry Halpin" <hhalpin@ibiblio.org>, "Jack Krupansky" <jack@basetechnology.com>, "Semantic Web at W3C" <semantic-web@w3.org>

Hi Richard

As Harry just said, the semantic web have well defined semantics for
rdfs:Class, owl:Class and owl:Thing. If you follow RDF semantics and
OWL semantics specs closely, they are defined in a very formal,
logically precise way. Classes are set of individuals, rdfs:Class is
the set of all RDF classes, owl:Class is identified with rdfs:Class in
OWL-FULL but not in OWL-DL. owl:Thing is a special owl:Class contains
all individuals in the universe. All those assertions are precisely
specified in the two documents.

*  RDF Semantics - http://www.w3.org/TR/rdf-mt/
*  OWL Semantics - http://www.w3.org/TR/owl-semantics/rdfs.html

Best

Jie

On Wed, Aug 27, 2008 at 8:49 PM, Richard H. McCullough
<rhm@pioneerca.com> wrote:
>
> I'm first trying to understand the definitions of "Class" and "Thing"
> in RDF/OWL.
>
> In the past, I have suggested different definitions, which I would have
> used in mKR.  But I only did that because I couldn't understand the
> RDF/OWL definitions.  I'm still trying to understand.
>
> I'm looking for help, for clarity.
>
> I think these questions are appropriate topics for the Semantic Web.
> If these questions can not be answered, then your "Semantic" Web
> is manipulating meaningless symbols.
>
> Dick McCullough
> Ayn Rand do speak od mKR done;
> mKE do enhance od Real Intelligence done;
> knowledge := man do identify od existent done;
> knowledge haspart proposition list;
> http://mKRmKE.org/
>
> ----- Original Message ----- From: "Harry Halpin" <hhalpin@ibiblio.org>
> To: "Richard H. McCullough" <rhm@pioneerca.com>
> Cc: "Jack Krupansky" <jack@basetechnology.com>; "Semantic Web at W3C"
> <semantic-web@w3.org>
> Sent: Wednesday, August 27, 2008 5:01 PM
> Subject: Re: Thing and Class
>
>
>> While I'm sure we all appreciate the work done on MKR, could we keep
>> MKR-specific posts to a MKR-list, not a Semantic Web list. While Richard
>> (Dick) McCullough is free to develop any interpretation of "class" and
>> "thing" he wants in MKR, of course, but the Semantic Web community uses the
>> ones in the W3C Specs, and I thought they were clear in the specs. If MKR
>> disagrees, that's fine (there's a long tradition of disagreeing about rather
>> vague high-level concepts like 'class' and 'thing'), but that's not a
>> question about the  Semantic Web.
>>
>> Richard H. McCullough wrote:
>>>
>>> I want to banish Class to the bookkeeping context, where it belongs.
>>>
>>> When two classes are equivalent, it means they have the same members,
>>> but different definitions -- which means they are in different contexts.
>>>
>>> When you merge the two contexts together, you get confusion.
>>> Which class are we talking about now -- Class or Thing?
>>> Which definition are we talking about now -- Class or Thing?
>>>
>>> The class "cup" abstracts all properties of its individual member "cups".
>>> That includes how a cup is used, what a cup is made of, etc.
>>>   cup subClassOf Thing;
>>> includes all those properties.  We might call this cup-the-Thing
>>> But when you say
>>>   cup type Class;
>>> you're in a different context - talking about cup-the-Class.
>>> That's what I refer to as the bookkeeping context.
>>>
>>> If you insist on dragging Class into the Thing context,
>>> then I recommend doing it in the form of a ClassSet.
>>>   cup ismem ClassSet;
>>>   ClassSet type Set;
>>>   Set  subClassOf  Thing;
>>>
>>> Dick McCullough
>>> Ayn Rand do speak od mKR done;
>>> mKE do enhance od Real Intelligence done;
>>> knowledge := man do identify od existent done;
>>> knowledge haspart proposition list;
>>> http://mKRmKE.org/
>>>
>>> ----- Original Message ----- From: "Jack Krupansky"
>>> <jack@basetechnology.com>
>>> To: "Richard H. McCullough" <rhm@pioneerca.com>
>>> Sent: Wednesday, August 27, 2008 2:49 PM
>>> Subject: Re: Thing and Class
>>>
>>>
>>>> But... if you get rid of Class, doesn't it then follow that subClass is
>>>> no longer defined or of comparable meaning?
>>>>
>>>> Is there a subThing that is "class-like"? I would imagine that subThing
>>>> is a decomposition of a Thing into the subThing's of which it is composed,
>>>> which is not "class-like" categorization, although it has some reductionist
>>>> appeal. But, a purely reductionist analysis does not look outwards to levels
>>>> of abstraction for how a Thing is externally viewed, perceived, and used.
>>>> Two "cups" would not have Class "cup" that recognizes an abstraction about
>>>> how a cup is used, but would be classified as to their material and form of
>>>> construction as Thing's.
>>>>
>>>> -- Jack Krupansky
>>>>
>>>>
>>>> ----- Original Message ----- From: "Richard H. McCullough"
>>>> <rhm@pioneerca.com>
>>>> To: "Semantic Web at W3C" <semantic-web@w3.org>; "KR-language"
>>>> <KR-language@YahooGroups.com>; "cyclify austin"
>>>> <cyclify-austin@yahoogroups.com>
>>>> Sent: Wednesday, August 27, 2008 4:59 PM
>>>> Subject: Thing and Class
>>>>
>>>>
>>>>>
>>>>> Since  Thing  subClassOf  Class;
>>>>> and     Class  subClassOf  Thing;
>>>>> it follows that  Thing  equivalentClass  Class;
>>>>>
>>>>> So, I say:  get rid of Class!
>>>>>
>>>>> Dick McCullough
>>>>> Ayn Rand do speak od mKR done;
>>>>> mKE do enhance od Real Intelligence done;
>>>>> knowledge := man do identify od existent done;
>>>>> knowledge haspart proposition list;
>>>>> http://mKRmKE.org/
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>
>
>
Received on Thursday, 28 August 2008 01:24:42 GMT

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