














• 
A belief net is a
directed



acyclic graph
composed of



stochastic
variables.



• 
We get to
observe some of



the variables
and we would



like to solve two
problems:



• 
The
inference problem: Infer



the states of
the unobserved



variables.



• 
The
learning problem: Adjust


the interactions
between



variables to make
the



network more
likely to



generate the
observed data.

