A note of the knapsack problem with special ordered sets

The knapsack problem with special ordered sets and arbitrarily signed coefficients is shown to be equivalent to a standard problem of the same type but having all coefficients positive. Two propositions are proven which define an algorithm for the linear programming relaxation of the standard problem that is a natural generalization of the Dantzig solution to the problem without special ordered sets/ Several properties of the corvex hull of the associated zero-one polytope are derived.