====== List nonmember ======
{{tag>lists}}
===== Description =====
Nonmembership of a list

**Source**:  The Art of Prolog
===== Download =====
Program source code: {{list_nonmember.pl}}
===== Listing =====
<code prolog>
/*
   nonmember(X,Xs) :- X is not a member of the list Xs.
*/
     nonmember(X,[Y|Ys]) :- X \== Y, nonmember(X,Ys).
     nonmember(X,[]).

%  Program 7.5    Nonmembership of a list
</code>
===== Comments =====