Help Needed

Hi everyone,
  I am new to the list. I have been trying to write some code in ECLiPSe
with no much success. I am having a problem with comparing some list values.
I have pasted down my code and I have marked the area where I need some help.
Thanks in advance and waiting for your reply.

Fahd
University of Arizona

:-lib(fd).
:-lib(listut).

	solve(Vars, Time):-
	
	N = 8,
	

	length(Vars, N),
	Vars::1..N,
	alldifferent(Vars),
	last(ALast, Vars),
	ALast = 1,

	vars_cost(Vars, AVar, Minor, Major),
	
	length(TVar, N),
	last(TLast, Time),


	var_assignment(Vars, Costs),
	
	compute_costs(TVar, Costs, AVar, Minor, Major),

	Tot #= TLast, 				
	minimize(labeling(Arcs), Tot).	

	vars_cost([], [], [], []).
	vars_cost([Arc|Vars], [Cost|Costs], [Mi|Mj], [Ui|Uj]):-
		element(Arc, [0, 10, 5, 12, 7, 1, 8, 9], Cost),
		element(Arc, [10, 0, 10, 10, 10, 10, 10, 10], Li),
		element(Arc, [100, 100, 100, 100, 100, 100, 100, 100], Ui),
		vars_cost(Vars, Costs, Mj, Uj).
	
	var_assignment(Vars, Cost):-
	
	Vars = [V1, V2, V3, V4, V5, V6, V7, V8],
	Cost = [C1, C2, C3, C4, C5, C6, C7, C8],

	Matrix = m(r(0,0,2,5,10,5,6,6), 
		     r(9,9,0,3,8,3,4,4), 
		     r(6,6,3,0,5,0,1,1),
		     r(5,5,7,10,0,13,11,11), 
		     r(0,0,2,5,10,5,6,6), 
		     r(5,5,2,5,10,5,0,0), 
		     r(9,9,0,3,8,3,4,4), 
		     r(0,0,2,5,10,5,6,6)), 
		

	wait_for([1, V1], subscript(Matrix, [1,V1], C1)), 
	wait_for([V1, V2], subscript(Matrix, [V1,V2], C2)), 
	wait_for([V2, V3], subscript(Matrix, [V2,V3], C3)),
	wait_for([V3, V4], subscript(Matrix, [V3,V4], C4)), 
	wait_for([V4, V5], subscript(Matrix, [V4,V5], C5)), 
	wait_for([V5, V6], subscript(Matrix, [V5,V6], C6)),
	wait_for([V6, V7], subscript(Matrix, [V6,V7], C7)),
	wait_for([V7, V8], subscript(Matrix, [V7,V8], C8)).
	
	
	compute_costs([], [], [], [], []).
	compute_costs([Ti|TRj], [Ci|Cj], [ACi|ACj], [Mi|Mj],[Ui|Uj]):-
		Ti #>= Li,
		Ti #<= Ui,
		Ci + ACi #= Ti,
		compute_rest_cost([Ti|TRj],Cj,ACj,Lj,Uj).
	
	
	compute_rest_cost([_],[],[],[],[]).
	compute_rest_cost([Ti,Tj|TRj],[Ci|Cj],[ACj|ACs],[Lj|Ls], [Uj|Us]):-
		Tj #>= Lj,
		Tj #<= Uj,
		Ti + Ci + ACj #= Tj,
%%%%%%%%%%%%%%%%%%%%%%
%		what I need over here is the following:
%		If Acj + Lj is greater than Tj then
%			I would like to assign Acj +Lj to Tj
%		otherwise 
%			do nothing
%
%		I have been trying to do that for some time with no success
%		Shedding some light on this issue will be highly appreciated. Thanks.
%
%%%%%%%%%%%%%%%%%%%%%%
		compute_rest_cost([Tj|TRj],Cj,ACs,Ls,Us).
	
	wait_for([], Goal):-
		call(Goal).
	wait_for([X|Xs], Goal):-
		(var(X) ->
			suspend(wait_for(Xs, Goal), 2, [X -> inst])
		;
			wait_for(Xs, Goal)
		).