UMLR — The definition of relative Time Events is ambigious

A relative Time Event i.e. after(x) as used as a trigger on a state machine transition is ambiguous as it is not clear when the earliest occurrence of this trigger could be.

If the originating state is entered at time T1 and the transition is taken at time T2 then providing T2 - T1 > x the event has happened 'after' x (in the common meaning of the word),
however if T2 - T1 = x it is not clear if the transition has been taken too early or not. This is because it is not defined whether 'after' means T2 - T1 > x or T2 - T1 >= x