 to refer to the j'th node in the
unrolled network, e.g., N25 = X(1,3), N33 = Y(1,3).
<p>
We assume the distributions P(X(i,t) | X(i,t-1)) and
P(Y(i,t) | X(i,t)) are independent of t for t > 1 and for all i.
Hence the CPD for N25, N37, ... is the same as for N13, so we say they
are in the same equivalence class, with N13 being the "representative"
for this class. In other words, we have tied the parameters for nodes
N13, N25, N37, ...
Note, however, that the parameters for the nodes in the first slice
are n