Re: Chaining and mixing of supertype-subtype and type-instance relationships

Hi Robert,

Am 04.10.2011 06:09, schrieb Robert Barta:
> On Sun, Oct 02, 2011 at 02:38:47PM +0200, Johannes Schmidt wrote:
>
>> E sub D isa C sub B sub A
>>
>> 1) D is an instance of B and A (due to transitivity in "C sub B sub A")
>> 2) E is an instance of C, B, and A (due to transitivity in "E sub D" and
>> "C sub B sub A")
>>
>> I found this in the latest TMRM draft in 5b) [1]:
>>
>> "[...] Additionally, whenever a proxy a is an instance of another c,
>> then a is an instance of any superclass of c: if x isa,m c and c sub,m
>> c' , then x isa,m c' is true."
>>
>> This supports 1), however I did not find any notes in the standards
>> supporting 2).
>>
>> What do you think?
> That TMRM tries to follow the "intuitive" meaning (whatever that is)
> of subclassing and instantiation? That E should be an instance of C
> is in no way intuitive to me. Do you have a real-life example?

E (T-Shirt Nike "Summer", color green, size M)* sub D (T-Shirt Nike 
"Summer") isa C (T-Shirt) sub B (Top) sub A (Clothing)

* this T-Shirt is also available in red and blue; all colors in sizes S 
to XXL

Clothing -> Top -> T-Shirt is part of a product taxonomy while T-Shirt 
Nike "Summer" is a product (classified as T-Shirt) and T-Shirt Nike 
"Summer", color green, size M is a product variant.

Best regards,
Johannes

> \rho
>