question about mutual <import>ing

Hello,

Consider a situation in which two schema documents contain <import>
information items which refer to one another.  Now suppose both schemas
contain references to components declared in the other schema.  I have two
questions:

1.  Is it valid for two schema documents to import one another?
2.  If the answer to 1. is yes, then is it also valid for both to contain
references to components declared in the other schema?

Please find attached an instance document and two schemas which exhibit
this behaviour.
(See attached file: bug2132.xml)(See attached file: bug2132A.xsd)(See
attached file: bug2132B.xsd)

Thanks for any help.
Neil Graham
XML Parser Development
IBM Toronto Lab
Phone:  416-448-3519, T/L 778-3519
E-mail:  neilg@ca.ibm.com