Lexical space for unsignedXXX types

(Applies to both 1.0 rec and 1.1 drafts.)

Sections 3.4.21~24.1 indicate that the lexical spaces for the unsigned 
types are "a finite-length sequence of decimal digits (#x30-#x39)", which 
means that signs are not allowed. That is, neither "-0" nor "+123" is 
valid.

But the Schema for Schemas says that the unsigned types are derived from 
their base types by simply specifying a lower/upper bound, which has no 
impact to the sign in the lexical space.

Which interpretation is correct?

Thanks,
Sandy Gao
XML Parser Development, IBM Canada
(1-905) 413-3255
sandygao@ca.ibm.com