**Go backward to** Solution to part (a)

**Go up to** 5 Arc Consistency

## Solution to part (b)

No, this constraint network is not arc consistent.
The arc *<X,Y>* is not arc consistent.
For *X=2* there is no *Y* such that *(X+Y)
mod 2 = 1* is true.

Computational
Intelligence online
material, ©David Poole, Alan Mackworth and Randy Goebel, 1999