What does this equation mean?

where h(s) is the hit rate measured directly among compounds actually synthesized and tested at docking-score bin s , and N(s) is the number of untested library members scored into that bin. Applying this to the D4 results produced an estimate of roughly 453,000 ligands across the full 138-million-compound library — a projection under an assumed score-to-hit-rate relationship, not a directly counted total. Confirmed hits included a 180-picomolar, subtype-selective D4 agonist, one of 81 new chemotypes with no prior literature precedent, 30 of which showed submicromolar activity. This is screening logic, not generative logic: nothing here proposes a molecule outside the pre-enumerated library, and the achievement is exhaustive search of a known space rather than invention of a new one.