On 15/06/2015 14:57, Steve Litt wrote:

> Just so I understand your answer in relation to my question, you're
> saying that "Start after" means "start sometime after", not "start
> immediately after". Right?

Yes, exactly this. It's just a prerequisite condition: "b must start
after a is started" and the converse requirement "b depends on a" is "a
must be started before b", which in the graph would be

b -> a

for both cases. If other things happen between a and b being started
and stopped, that's totally fine.