BDS false positive rate w.r.t. hash functions (a) and k -value (b). FP rate as a function of the number of indexed k-mers (in log scale). Plain lines correspond to theoretical predictions, whereas star points correspond to empirical values obtained with simulations. (a) This figure was obtained for k = 33 for balanced and unbalanced functions and some combinations of them. The combination entitled "4 functions" is composed of the 3 balanced functions plus one unbalanced. (b) For several values of k, this figure was obtained for a combination of 4 hash functions: all three balanced plus one unbalanced.