If a word does not appear in the query at all, its weight becomes equal to the usual tf w,s idf w,S : The overall novelty ranking formula is based on the query-dependent PageRank introduced in Equation (2).
since we already incorporate the relatedness to the query in these two settings, we focus only on related sentences and thus may drop the relatedness to the query part from (2): We set λ to the same value as in OTTERBACHER.