The major problem of the interaction between these three formats is that they differ in expressive power, formal properties and with respect to the existence or non-existence of an interpretation in certain types of models.
In other words, intertranslatability is not a priori given, for the three types of description languages. The Genelex project use an ER model to represent the conceptual model. This formalism express a lot of integrity constraints via the typing of objects and relations and through the arities of the relationships. To maintain the model readeable the constraints on cooccurence of features values are expressed in a pseudo-natural language rules. All these constraints are explicitely reported when translating the EA schema in the SGML DTD. This translation follows strict rules. The methodology group will interact with the EAGLES formalisms group and with entity relationship model experts in the consortium to precise the interrelationships between the three representation formats, becausethe level-wise workgroups will want to represent their proposals in a consistent way which then can be interpreted consistently across groups, and also from outside EAGLES. This point needs further clarification.