Abstrakt
Nested workflows are used to formally describe processes with a hierarchical structure similar to hierarchical task networks in planning. The nested structure guarantees that the workflow is sound in terms of possibility to select for each involved activity a process that contains the activity.
However, if extra synchronization, precedence, or causal constraints are added to the nested structure, the problem of selecting a process containing a given activity becomes NP-complete. This paper presents techniques for verifying such workflows; in particular, they verify that a process exists for each activity.