RE: some basic questions, thanks

1.       When B and C are equivalent class, A is not subclass of B and
C.
2.       No difference. But A can also be the subclass of the union of B
and C.
3.       Sorry, I can’t understand what you mean.
4.       Subclasses describe the different facet of its superclass.
5.       if A is the subclass of the union of B and C, and a*A, then a*B
or a*C.
if A is the equivalent class of the union of B and C, and if a*A, then
a*B or a*C and if b*B*C then b*A
 
-----Original Message-----
From: Li Qin [mailto:bethqin@hotmail.com] 
Sent: 2003年9月19日 11:32
To: zhubin@cai.pku.edu.cn
Cc: www-rdf-logic-request@w3.org
Subject: RE: some basic questions, thanks
 

Thanks. Just more discussions:
1. Intersection, as a set operation to get the common part of two sets,
does not introduce any hierarchy at all. Here, if A is the intersection
of B and C means that A is the subclass of B and C, this intersection
introduces hierarchy. 
2. "If A is the subclass of union of B and C" does not mean that A is
the union of B and C. My question concerns the case that A is the union
of B and C.
If A is the union of B and C, the instances of B and C are instances of
A.
If A is the superclass of B and C, the instances of B and C are
instances of A.
What is the difference?
3. If A is the complement to B, A is the difference between an unkown
class and B. Does this unkown class the union of A and B or the
superclass of A and B?
4. When do you use a class instead of its subclasses for their
instances, if they all have their own instances? 
5. If A is the union of B and C. What is the relationship between the
instances of A, B and C?
Thanks.
 
 
>From: "Zhu Bin" 
>To: "'Li Qin'" 
>Subject: RE: some basic questions, thanks 
>Date: Fri, 19 Sep 2003 09:51:34 +0800 
> 
>My opinion, maybe it’s wrong: 
> 
>1. I think it does and when I express A is the subclass of both B and
C, 
>I can only use that A is the intersection of B and C. and it’s 
>different between that A is the subclass of the intersection of B and C

>and A is the equivalent class of the intersection of B and C. 
>2. I think it’s not exactly. If A is the subclass of union of B and C,

>then the instances of B and C are not sure instances of A, if A is the 
>equivalent class of union of B and C, then the instances of B and C are

>surely instances of A. 
>3. I think it’s not exactly either. I think you know the reason. 
>4. Yes, it does. 
> 
>If I have anything wrong, would you please remind me? 
>Thanks very much 
> 
>Best regards, 
>Zhu Bin 
> 
>-----Original Message----- 
>From: www-rdf-logic-request@w3.org
[mailto:www-rdf-logic-request@w3.org] 
>On Behalf Of Li Qin 
>Sent: 2003年9月19日 8:49 
>To: www-rdf-logic@w3.org 
>Subject: some basic questions, thanks 
> 
>1. If A is the intersection of B and C, does it mean that A is the 
>subclass of both B and C? 
> 
>Is it correct that the instances of A are also instances of B and C 
>while the common instances of B and C are also instances of A? 
> 
>2. If A is the union of B and C, the instances of B and C are also 
>instances of A. How does it differ from the relationship between 
>subclass and superclass where the instances of the subclass are also 
>instances of the superclass? 
> 
>Does A have its own instances in addition to the instances of B and C? 
> 
>3. If A and B are complement of each other, does it mean there exists a

>C who is the union of A and B or the superclass of A and B? 
> 
>4. If a class has subclasses, does this class have instances of its own

>in addition to the instances of its subclasses? 
> 
>Thank you in advance. 
> 
> 
> _____ 
> 
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