The member function
lmember
tells whether a specified element is in a specified list. It returns 1 or 0 accordingly:
lmember(11,
[5, 7, 11, 13]) ==> 1
lmember(12,
[5, 7, 11, 13]) ==> 0
lmember(3,
[ [ [1, 2, 3], [2, 3] ], [ [3], [] ] ]) ==> 0