This assumption does not hold for certain kinds of forwards.

This assumption of independence does not necessarily hold in a real situation.

Granted that the first assumption held true, then the second must have broken down!

More likely, the assumptions behind molecular clocks do not hold exactly.

Sieverts' law shows a case when this assumption does not hold.

If these assumptions do not hold, markets could be in for another troubling year.

But the new animal results have caused experts to ask whether their basic assumptions hold true.

Therefore most of the points put forward can be dismissed as the assumptions on which they are based cannot hold in the real world.

Indeed, if that is not the case to start with, a different set of intervals can be picked for which these assumptions hold.

The idea behind it is that the assumptions made when the brand was established may no longer hold true.