|s1> => find-topic[words] (|thomas>) |s2> => find-topic[words] (|thomas> + |ronald>) |s3> => find-topic[words] (|thomas> + |ronald> + |richard>) |s4> => find-topic[words] (|thomas> + |ronald> + |richard> + |bill>) |s5> => find-topic[words] (|thomas> + |ronald> + |richard> + |bill> + |barack>) |s6> => find-topic[words] (|thomas> + |ronald> + |richard> + |bill> + |barack> + |george>) |s7> => find-topic[words] (|thomas> + |ronald> + |richard> + |bill> + |barack> + |george> + |james>) |s8> => find-topic[words] (|thomas> + |ronald> + |richard> + |bill> + |barack> + |george> + |james> + |jimmy>) |list> => |s1> + |s2> + |s3> + |s4> + |s5> + |s6> + |s7> + |s8>