BPMN21 — Legal BPMN models and “lack of synchronization"

) Chapter/Section 10.2. Page 157. Table 10.3. Row “completionQuantity”. It says:
“This attribute defines the number of tokens that MUST be generated from the Activity. This number of tokens will be sent down any outgoing Sequence Flow …”

ii) Chapter/Section 13.3.5. Page 452. It says:
“Each incoming gate of the Complex Gateway has an attribute activationCount, which can be used in an Expression as an integer-valued variable. This variable represents the number of tokens that are currently on the respective incoming Sequence Flow.”

iii) Chapter/Section 14. Page 461. It says:
“To map a BPMN orchestration Process to WS-BPEL it MUST be sound, that is it MUST contain neither a deadlock nor a lack of synchronization. A deadlock is a reachable state of the Process that contains a token on some Sequence Flow that cannot be removed in any possible future. A lack of synchronization is a reachable state of the Process where there is more than one token on some Sequence Flow.”

COMMENTS:

>From and (ii) can be deduced that a correct BPMN model allows Process instances with Sequence Flows containing more than one token.

According to (iii) this is considered a “lack of synchronization”, which prevents the mapping to WS-BPEL.

SUGGESTIONS:

Clarify whether “lack of synchronization” means that the Model is illegal or not.