Consequently, rec(i, u) is the sum of the weights of all constraints that,
in conjunction with the specific project context (SRSu),
support item (i) to be in the result set.
E wc
in the denominator normalizes the utility score to the range 0..1. In cases where not all of the hard constraints are able to be fulfilled the score is set to 0.
This approach was already proposed in where constraints have been learned from past user interactions.