Incoherence of min/maxOccurs property between IM and SDMX-ML

[dosse]

A user highlighted an inconsistency in the documentation between the IM and the message format implementations (SDMX-ML and SDMX-JSON), see: sdmx-twg/sdmx-json#124. Indeed, when constructing the message formats, sometimes some changes are made to generalise the approach and make it more coherent. Also, sometimes certain aspects may not have been seen when writing the IM document.

More specifically, you can see here and here that the maxOccurs and minOccurs parameters were moved from the component definitions (as described in the IM) into the SDMX-ML RepresentationType, thus into CoreRepresentation (inside concepts) and LocalRepresentation (inside the component definitions in the DSD). The same was done in SDMX-JSON.
It would seem to me that this inconsistency should be addressed by updating the IM document.

By the way, there is also an inconsistency about the meaning of minOccurs. In some places, the IM still says wrongly that minOccurs=0 means that a component is optional. In other places it mentions the finally agreed approach where mandatory/optional is a separate property.