Business Process Management

Concepts, Languages, Architectures (Second Edition)

YAWL semantics (1)

YAWL gradually enhances Workflow nets by introducing OR-joins and a flow syntax that allows arbitrary cycles. Reconsider the different solutions regarding the synchronizing merge from the lecture as well as the extended description found in

W.M.P. van der Aalst and A.H.M. ter Hofstede. YAWL: Yet another Workflow Language (Revised Edition). (

a) Discuss the different solutions for the synchronizing merge regarding to the following process model:

b) While the model from 1) requires to always execute A and B, as well as C or D, a change in the requirements demands another execution of A if the quality check E fails. Discuss the problems that arise regarding to the synchronizing merge in the extended process model (which is still a conform YAWL workflow):

More information on workflow nets can be found in the book in chapter 4.4. A solution to this exercise can be found here.