Note this schema is NOT a normative schema - -
It contains types derived from all the builtin simple type definitions
with the same local name but in a distinct namespace, for use
by applications which do no wish to import the full XMLSchema
schema. Since derivation is not symmetric, unexpected results may
follow from mixing references to these definitions with references
to the definitions in the XMLSchema namespace. For example,
although dt:positiveInteger is derived from xs:integer, the converse
does not hold.