I'm working on an implementation of the MIX NISO standard in xml.



I'm confused by an apparent mismatch between the data dictionary http://www.niso.org/standards/resources/Z39_87_trial_use.pdf

and the MIX documentation



While a number of elements are 'Mandatory' in the Dictionary (e.g. CompressionScheme)

All elements are minoccurs=”0” in the Schema (i.e. Optional)


Any feedback gratefully received




Hervé L’Hours