As a result of these insights, we settled for breaking the piecewise linear functions ητ at 0.4, 0.6, 0.8, with the greatest slope in the interval [0.6, 1.0] because that is the part where the expert considers the differences of match scores to be most important. Because the expert considered a single indication of GNPS to be indifferent to a combination of indications from Sirius and ISDB-LOTUS with a good Tanimoto match, we set the tradeoffs so that k(α) = k(α ′ ) with α = (0.8, 0.4, 0.4; 0.4, 0.4, 0.4) and α ′ = (0.4, 0.8, 0.8; 0.4, 0.4, 0.7) (thus ηg(0.8) = ηs(0.8) + η i (0.8) + φ s,i (0.7, 0.8, 0.8)). From the reasoning of the expert facing the precise questions, it more generally appeared that the gain of a Tanimoto match between Sirius and ISDB-LOTUS was higher than the one between GNPS and Sirius, itself higher than the one between GNPS and ISDB-LOTUS. We considered that φ τ,τ ′ should behave linearly in t τ,τ ′ and also in ητ (cτ ), η τ ′ (c τ ′ ), because ητ absorbs the non-linear effects of the match score scale (thus ∂φ τ,τ ′ ∂ητ must be constant). Note that the choice ητ (0.4) = 0 is arbitrary as only the comparison of values of k matter for ordering candidate ions. GNPS returns no answer for some MS/MS datum when using a 573 standard query q(6, 0.02) that demands to consider only possible search (GNPS I , Fig. ). This approach queries the GNPS starting 580 with a highly demanding query, q(6, 0.02), and progressively relaxes 581 the constraints, allowing for a 0.1 dalton exact mass difference, then 582 10 dalton, . . . , then also relaxing the required number of shared peaks.