Extend results to causally-closed communication models (bag and causally ordered systems)

Determine whether the main theorems and constructions established in this paper for multiparty session types—those relying on causal closure—extend to other causally-closed communication models, specifically bag systems and causally ordered systems, by formally proving that the stated implications and decidability results hold in those models.

Background

The paper’s results frequently exploit the property of causal closure of the communication model, which holds for the peer-to-peer (FIFO) model but not for the synchronous model. The authors suggest their framework could be generalised beyond the specific models studied, provided causal closure is satisfied.

They specifically point to bag and causally ordered systems as candidate models, noting that these satisfy causal closure, and conjecture that their results would carry over. Formal confirmation would require re-establishing the core equivalences and decidability arguments under these models.