> I think I was trying to 
> draw the first conclusion based on what I remember from my 
> experiments with LRE stylesheets. 

Please don't do this. If you try to reverse-engineer a language
specification by experimenting with various candidate instances, (a) it will
take a very long time, and (b) you will probably end up inferring some
pretty weird rules.

There is a better way. Read the spec.

Michael Kay
http://www.saxonica.com/