> From: Jens Østergaard Petersen
> 
> Your document validates with me as well, because the MODS schema
> references the XLink schema at
> <http://www.loc.gov/standards/xlink/xlink.xsd>.
> 
> My point was that the Library of Congress XLink schema does not accord
> with the W3C XLink schema in the naming of simpleLink/simpleAttrs, so
> if you change the schemaLocation for the XLink schema in the MODS
> schema and substitute it with a reference to the standard XLink schema
> at <http://www.w3.org/1999/xlink.xsd>, your document becomes invalid.

Ok, thanks, I see the problem now (no need to explore Oxygen, etc. any
further).

line 33 of the LC XLink schema says:
<attributeGroup name="simpleLink">

which corresponds to line 111 of the W3C XLink schema which says: 
<attributeGroup name="simpleAttrs">

And so with the mismatch of names, "simpleLink" vs. "simpleAttrs", if you
try to substitute the W3C schema reference in the MODS schema, the MODS
schema itself won't validate (I tried it) because the schema itself
references "simpleLink".

This is an easy problem to fix and the fix would be completely transparent.
We could make the change in the LC XLink schema, and change the references
in the MODS schema, and there would be no need for any changes to MODS
instance. 

Well, It isn't quite that simple. (But almost.) The LC XLink schema is used
not only by MODS, but also by METS. So unless we coordinated this change
with the METS folks, we would also need to have separate XLink schemas (a
"MODS XLink schema" and a "METS XLink schema") and change the reference in
the MODS schema to point to the MODS XLink schema.   Also a trivial change. 

But I am not sure why this change is warranted.  What is the need to
reference the w3c XLink schema rather than the LC schema? 
If there is a need to do this, we can make theses changes.

--Ray