I have a series of actions A, B, C and D which fire sequentially, each in a different step. As long as A doesn't fire again before D, then every firing of action A must always lead to D. However, it is possible A will fire again before D, starting the series of actions again.
So for example, all of the below sequences of steps are valid:
A, B, C, D, A, B, C, D
A, B, A, B, C, D
A, B, A, B, A, B, A, B, C, D
A, A, B, A, A, A
A, A, A, A, A, A
So my question is: How can I state some fairness property that describes that A will eventually lead to D, but only if A doesn't fire again before D.