This subsection illustrates VE1
by walking through an example.
Consider computing the
in the deputation Bayesian
network shown in Figure 2.
Suppose the elimination ordering 
is: a, b, c, 
,
, 
, and 
.
After the first step of VE1 ,
Now the procedure enters the while-loop and it sums out the
variables in 
one by one.
After summing out a,
where 
.
After summing out b,
where 
.
After summing out c,
where 
.
After summing out 
,
where 
.
After summing out 
,
where 
.
After summing out 
,
where 
.
Finally,
after summing out 
,
where 
.
Now the procedure enters step 3, where there is nothing
to do in this example. Finally, the procedure returns
, which is
, the required probability.