Wht '<=' ? rather than '<'?

Dear XML Schema WG members,


Summary
-------
the order relation of dateTime value is not good. So please think about
it again.



Explanation
-----------
In section 3.2.7.3 of the spec part 2,

The order relation of dateTime value is specified as:

> C.Otherwise, if P contains a time zone and Q does not, compare as follows: 
> 
> P <= Q if P <= (Q with time zone -14) 
> P >= Q if P >= (Q with time zone +14) 
> P <> Q otherwise, that is, if (Q with time zone -14) < P < (Q with time zone +14) 

There is no definition of relation '<' and '>'.
And this is the source of all troubles.

Why define '<=' instead of '<' ?



In the section 2.4.1.2 of the spec, it says

> partial order relations have the following rule: 
> 
> for every pair (a, b) from the value space, either a < b or b < a or
> a = b or a <> b where the symbol <> indicates that an order between the two
> values cannot be determined. 

So to be consistent with this definition of partial order,
the only acceptable definition of '<' is:

|  P<Q  iff P<=Q
|  P>Q  iff P>=Q


which results in (from the definition of '<=')

P < Q  iff   P <= (Q with time zone -14) 



In summary, defining '<=' requires additional reasoning for everyone who
read it, and very confusing. So please change it to define '<' directly.


regards,
----------------------
K.Kawaguchi
E-Mail: k-kawa@bigfoot.com

Received on Tuesday, 13 February 2001 18:29:41 UTC