Now consider the case of probabilistic uncertainty. We use
to denote the shadow with label
, as well as the random variable for that shadow in the joint/multivariate distribution. For shadows
, the joint distribution is then
, in which a specific entry is
. In writing formulas and outlining algorithms, we usually shorten the repeated variables to ``
'' on both the left hand side (LHS) and the right hand side (RHS) of an expression. In such cases, the combined ``
'' on the LHS and RHS denote the same set of random variables. For example,
is shortened to
.