We introduce an effective batch updating algorithm, and present performance measurements on a subset of the Reuters newswire corpus that show that a 12.5% to 50% split of the documents into corpus and update vectors leads to a three to four fold speedup over a complete rebuild.
for deletions, we let denote  index permutation to remove demoted terms e i i-th standard base We associate every update u = (i, v) ∈ U with two term frequency vectors.