(
http://www.ivoa.net/internal/IVOA/Utypes/WD-Utypes-0.3-20090522.pdf)
@2.1 "data model elements": need to agree what these may be. That is need to know the syntax of data modelling. When in UML this might mean deciding on using Class diagrams. Or choosing a particular UML profile. Or possibly a custom language defined for "data modelling in the VO". This is what we have done in
SimDB and therefore we were able to define ("BNF") and implement (XSLT) rules for deriving Utypes from the data model.