Collaborative work processes are widespread, and call for sophisticated modelling techniques to guarantee that the in-focus process is able to suitably handle all the relevant ways in which external, uncontrollable participants can influence the overall behaviour. In the presence of external actors, one needs to distinguish the internal, controllable nondeterminism of the in-focus process from the uncontrollable nondeterminism of external participants. While collaborative processes have been previously studied in the context of declarative processes, where specifications distinguish how different sources of control interact, no study along this line exists in the context of the DECLARE declarative process modeling framework. To this end, we introduce “collaborative DECLARE ” (coDECLARE), where activities are assigned to the internal orchestrator or to external participants, and constraints are partitioned into conditions on how the external participants can interact with the in-focus process, and conditions that must be guaranteed by the in-focus process itself, framing the resulting specifications in style of assume-guarantee (behavioral) contracts. We discuss the conceptual and explain how central tasks such as that of DECLARE consistency and enactment have to be revised for coDECLARE. Moreover, we show how the resulting tasks can be encoded into corresponding realisability and reactive synthesis tasks for LTL specifications on finite traces.
