All Different
	n Suppose Dx = {2,3} = Dy, Dz = {1,2,3} n All the constraints xy, yz, zx are all arc consistent n e.g. x=2 supports the value z = 3 n The single ternary constraint AllDifferent(x,y,z) is not! n We must set z = 1 n A special purpose algorithm exists for All-Different to establish GAC in efficient time n Special purpose propagation algorithms are vital