The image shows RRF search score formula.

Where:

r – A hybrid search result
S – The result sets, s is either keyword (text) search results OR semantic (vector) search results.
penalty_s – The rank_penalty parameter for the result set s . This value is either vector.rank_penalty or text.rank_penalty.
ranks_s(r) – The rank of the result r within the result set s . If r is not present in s , then set ranks_s(r) value to result_max(s). The result_max(s) value is either vector.result_max or text.result_max.