> Perhaps you know some other software which supports this sort of algebra?
> (The closest I can think of is Bayesian network software, but it is
> non-symbolic and expects specification of factorized probability
> distributions as input.)
>
When you define a set of conditional probabilities, you get a graph of
dependencies. If they are not well defined, then they are incompatible
with a compound distribution involving all variables, which are the
nodes. This sort of things are studied by Graphical Models.
As an starting point, I'd take a look at http://www.ci.tuwien.ac.at/gR/
--
Mario Rodriguez Riotorto
http://www.telefonica.net/web2/biomates