Andreas Launila wrote:
> Since we now have to start exploring the search space we make a guess
> that e=4. Propagating the constraints once again with e given the domain
> 4 will directly result in a failure, so we backtrack and now know that
> e!=4. With that information we redo the propagation and directly end up
> at the solution with no need to explore any further. So in total we only
> need to explore 4 out of 9^2*10^6 nodes in the search space.
> 

The last part is probably a bit misleading/incorrect. We are not
directly exploring the space of all possible assignments when we branch,
so saying that we have explored 4 nodes in that space is incorrect (i.e.
we have not just explored 4 possible assignments, but we have visited
just 4 nodes in our search space).

-- 
Andreas Launila