0
|
3225 Views
|
3 Replies
|
0 Total Likes
View groups...
Share
GROUPS:

# ForAll statement being ignored

Posted 9 years ago
 Help much appreciated. I'm trying to specify a PDF for the results of a set of experiments. Each experiment's result is Poisson distributed with a constant expectation ('factor'). The results themselves are given by score[g] for experiment number g. This defines the set of probability distributions: probresult[g_, factor_] := PDF[PoissonDistribution[factor], score[g]]  Now, if I ask for the expression for a specific result (say, g=3), I get a conditional expression that expresses the Poisson distribution for score>=0, and 0 otherwise - which is fine. If I want to get rid of the conditional, I can add the statement score>=0  and it then returns the unconditional distribution because we've assumed it's weakly positive. But if instead I add the stronger assumption ForAll[x,score[x]>=0]  we are back to the conditional output. I can't work out how to get it to infer score>=0 from ForAll[x, score[x]>=0] What am I doing wrong? Many thanks in advance.
3 Replies
Sort By:
Posted 9 years ago
 Aha - cracked it with: probresult[g_, factor_] := Simplify[PDF[PoissonDistribution[factor], score[g]], Assumptions -> score[g] >= 0] Very many thanks!
Posted 9 years ago
 Many thanks - that's exactly what I'm trying to do. With an arbitrary x elements, how can I declare the assumption that score[x]>0 for every element?
Posted 9 years ago
 Are you trying to do Assumptions -> ForAll[x, score[x] >= 0] ? I don't think ForAll works as an assumption. It's used inside Reduce or Resolve.