ancestors in the past.
Hence we need to use approximations.
<p>
A popular approximate inference algorithm for discrete DBNs, known as BK, is described in
<ul>
<li>
<A HREF="http://robotics.Stanford.EDU/~xb/uai98/index.html">
Tractable inference for complex stochastic processes </A>,
Boyen and Koller, UAI 1998
<li>
<A HREF="http://robotics.Stanford.EDU/~xb/nips98/index.html">
Approximate learning of dynamic models</a>, Boyen and Koller, NIPS
1998.
</ul>
This approximates the belief state with a product of
ma