Suppose, without any observations, we eliminate F. What factors are removed and what factor is created. Give a general rule as to what variables are joined when a variable is eliminated from a Bayesian network.
We remove the factors P(F|D), P(H|E,F), P(I|F,G) and replace them with f1(D,E,H,I,G).
The general rule is that we join the parents of the node being removed, the children of the node being removed and the children's other parents.