Suppose there were three events that could be done in any order. Let these events be A, B and C. There are a total of 6 possible ways the events can be performed.
However, this time, there is a restriction. B can only be performed after A. In other words, A must be performed before B can, and ACB is also accepted.
Your task is to find a general formula for X number of events, and Y number of restrictions.
None of the events is mentioned in more than one restriction.
The relationship between events and restrictions is easy! But it involves a new variable.
If you call 3 events term 1, you can call 4 events (and the corresponding restrictions) term 2, and so on and so on...
You multiply the restrictions by 2, and if the term number is odd, you add on 1 after, to get the events.
2y+1 (if term is odd) = x
It's not that general, but general enough, I think. One question though  by restriction, do you mean strictly one event must come before/after another event, or do you mean things like one event must be first, one last, etc. Or is the whole problem much more complicated???

Posted by Angela
on 20050215 19:10:59 