Make process start and end explicit
Always depict start and end events.
✔ How to
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
✘ How NOT to
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
Notes
According to BPMN spec start and end events aren't obligatory -
an activity without incoming sequence flows is treated as implicit process start, activity without outgoing sequence flows is implicit end.
However it's better to avoid such diagrams because they may be misunderstood.
Exceptions
Ad-hoc subprocess:
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
Author(s)