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%
%  mul(S,X): X is the product of all numbers in the set S
%
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:-consult_lib.  

mul(S,X) :-
        mul3(S,1,X). 
mul3({},X,X). 
mul3(S,X,Y) :-
        xless(S,A,SS) &
        Z is X * A &
        mul3(SS,Z,Y).  


% Sample goal:
%
% {log}=> mul({3,2,4},R). 
% R = 24