Help! Problem with sorting an list...

[Man1234]

How can i solve this problem by prolog????

A,B,C,D,E,F and G stand for 7 consecutive integers

D is 3 less than A
B is the middle term
F is as much less than B as C is greater than D
G is greater than F

Question: What is the order of the variables?

How can I exactly declare the rules and facts???
Please help... It's urgent.....
^___^

 

[pimi]

Hello.
This program enumerates all patterns.
Please add restriction to this program.

ins(X, L, [X|L]).
ins(X, [L1|LT], [L1|RT]) :- ins(X, LT, RT).

perm([], []).
perm([L1|LT], R) :- perm(LT, W), ins(L1, W, R).

main(A, B, C, D, E, F, G) :-
perm([1, 2, 3, 4, 5, 6, 7], [A, B, C, D, E, F, G]),
D < A,
...,
G > F.

I can't understand &quot;B is the middle term&quot; and
&quot;F is as much less than B as C is greater than D&quot;.
Please write algebraically.
&quot;B = 4&quot; and &quot;C - D = B - F&quot; ??