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.