Alldifferent filtering

Hi,

Can you please tell me what kind of filtering Eclipse applies to the
'alldifferent' constraint? The documentation states that there are two
kinds of filtering, AC on the binary decomposition and SOME global
filtering based on 'exhaustion of all sub-ranges of possible values'.
These last sentence is a bit vague to me. 

The program below shows some behaviour that makes me confused about the
filtering algorithm.

Thanks in advance,
Willem Jan van Hoeve


:- lib(fd).
:- lib(fd_global).

wj1 :-
	A1::[1,3],
	A2::[1,3],
	A3::[1,2],

	L=[A1,A2,A3],

	fd_global:alldifferent(L),

	(foreach(X, L) do writeln(X)).

wj2 :-
	A1::[1,3],
	A2::[1,3],
	A3::[2,3],

	L=[A1,A2,A3],

	fd_global:alldifferent(L),

	(foreach(X, L) do writeln(X)).

wj3 :-
	A1::[1,3],
	A2::[1,3],
	A3::[1,2,3],

	L=[A1,A2,A3],

	fd_global:alldifferent(L),

	(foreach(X, L) do writeln(X)).

wj4 :-
	A1::[1,3],
	A2::[1,3],
	A3::[2,3,4],

	L=[A1,A2,A3],

	fd_global:alldifferent(L),

	(foreach(X, L) do writeln(X)).