An efficient heuristic approach to solve the unate covering problem

The paper presents a new approach to solve the unate covering problem based on exploitation of information provided by Lagrangean relaxation. In parti cular, main advantages of the proposed heuristic algorithm are the effectiv e choice of elements to be included in the solution, cost-related reduction s of the problem, and a good lower bound on the optimum. The results suppor t the effectiveness of this approach: on a wide set of benchmark problems, the algorithm nearly always hits the optimum and in most cases proves it to be such. On the problems whose optimum is actually unknown, the best known result is strongly improved.