Let A = {a1, . . . , an} be a set and F = {F1, . . . , Fm} a family of subsets of A. A subset H ⊆ A has the hitting set property, or is a hitting set, iff H ∩ Fi 6= ∅ for 1 ≤ i ≤ m (i.e., H “hits” each set Fi). If we are given a cost function c : A → N, the cost of H is ∑ a∈H c(a). A hitting set is of minimum cost if its cost is minimal among all hitting sets. The problem of finding a minimum-c...