Suggestions for XML 1.1

Dear XML Schema working group,



I am a newbie in working with schema s but currently what I am missing is 
the following:



1)       A way to specify constraints like: attribute/element MIN < 
attribute/element MAX. I think that specification of such constraints could 
be done via Xpath. Or if you have a collection of elements of the same type 
a particular attribute can only exists on one of those elements. Defaults 
that depend one other values etc. I see lot s of possibilities in this area.

2)       Choice options for attributes ie. if one attribute is specified 
the other is prohibited and vise versa.



If this can be done now I apologize in advance, I that case I d really 
appreciate it if someone could e-mail me how this can be done.



Robert