On tightening cover induced inequalities

Here we describe computationally efficient procedures for tightening cover induced inequalities by using 0-1 knapsack constraints and, if available, cliques whose variables are included in the cover. An interesting application is the case where the cover is implied by the knapsack constraint. The tightening is achieved by increasing the coefficients of the cover inequality. The new constraint is 0-1 equivalent to and LP tighter than the original one. The computational complexity of the procedures is O(n log n), where n is the number of variables in the cover. © 1992.