Before revision:  We give a generalization of the greedy algorithm for the case of interval objective function. For the discrete optimization problems that we consider, the algorithm gives a set of all possible greedy solutions and the set of all possible values of the objective function for the solutions.
After revision:  We give a generalization of the greedy algorithm for the problems. Using the algorithm, we obtain the set of all possible greedy solutions and the set of all possible values of the objective function for the solutions.