Model projects/meetings w ArchiMate

[Glassboy]

Relationship between elements
Collaboration -> Collaboration: composition
My argument is that if CWIX ESC dies, all "instances", i.e. CWIX ESC 2018/9... dies as well.

I'm not sure about this die.  It's Archimate.  Literally the only way your model knows about time is if you relate a plateau element to another element in your model.

[Hurra]

I consider aggregation and composition hierarchical relationships. As far as I now, composition: the child dies with the parent, aggregation: the child can live without the parent. That is the reason I chose composition. Perhaps it's different with Archimate?

We have started modeling according to my latest post, and I emphasized consistency to be able to do corrections/alterations later on with scripts or similar.

We do use the plateau element, but they are very big time-wise. Might be a good idea to relate the collaboration, aka meeting, to the plateau.

[Glassboy]

I consider aggregation and composition hierarchical relationships. As far as I now, composition: the child dies with the parent, aggregation: the child can live without the parent. That is the reason I chose composition. Perhaps it's different with Archimate?

Archimate says that composition and aggregation are inspired by UML.  I'm not convinced that any one involved with creating Archimate has a very deep understanding of UML (or modern ICT for that matter).  The difference in Archimate between composition and aggregation is an element can only be in one composition set but can be in multiple aggregation sets.

As practically you could combine two meetings into one time slot where there are common points of interest I'd tend to go with aggregation.  Any cross over of related elements would be much less messy.

[Paolo F Cantoni]

I consider aggregation and composition hierarchical relationships. As far as I now, composition: the child dies with the parent, aggregation: the child can live without the parent. That is the reason I chose composition. Perhaps it's different with Archimate?

Archimate says that composition and aggregation are inspired by UML.  I'm not convinced that any one involved with creating Archimate has a very deep understanding of UML (or modern ICT for that matter).  The difference in Archimate between composition and aggregation is an element can only be in one composition set but can be in multiple aggregation sets.

As practically you could combine two meetings into one time slot where there are common points of interest I'd tend to go with aggregation.  Any cross over of related elements would be much less messy.

Took the words off my keyboard! 
To extend your point, if (as it may happen) a meronym may only exist in at most one aggregation at a time, you then ask the question about destruction with the holonym to determine if it is a composition or aggregation.

But, I reiterate, the relationship between a classifier (archetype) and its instances is NOT one of meronymy.  Notwithstanding that, colloquially we say a classifier "has" instances.  Meronymy ONLY exists between instances (of classifiers).

Paolo