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

Dear XML Schema WG members,

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

In section 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 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.

E-Mail: k-kawa@bigfoot.com

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