Overlap between spec and profile docs.

[Gary P Cole <Gary.P.Cole@Sun.COM>]

I'm thinking about XPath at the moment, but I think the issue is 
broader. We've agreed that an SPMLv2 provider MUST support XPath 2.0 
abbreviated location paths (and MAY support arbitrary XPath 
expressions), but where does this language belong?

I want to describe XPath in the specification (because XPath and the 
requirement to support abbreviated location paths seems general), but 
one might argue that the issue of XPath support is specific to the XSD 
profile.  I'm not trying to argue that specific point right now--I'm 
after something else.  If we *assume* for the moment that XPath is 
irrelevant to the DSML profile, then should the specification (or should 
the XSD profile) describe Xpath support?

Suppose that we decide that a certain aspect of behavior should be 
described in the specification--because we believe that the requirement 
is general (or is general enough to apply to more than one profile).  
Should a specific profile be allowed to override the specification in 
any way it sees fit, or should a profile only be allowed to *add to* the 
specification?

Other standards groups have probably already tackled questions like 
these.  PSTC members (with more experience than I have) may already know 
the convention.  If so, please share.