Enforced Separation in 3-Dimensional Assignment) Consider the 3-dimensional assignment problem of Example 10.7 that involves a set of jobs J, a set of machines M, and a set of workers W. We assume that each of the sets J, M, and W contains n elements, and that the constraints are equality constraints. Suppose that the problem is -separable, in the sense that for some βjm and γmw, and some ≥ 0, we have
(a) Show that if the problem is solved with 3-dimensional assignment obtained achieves the optimal cost of the original problem within 2n.
(b) Suppose that we don't know 
and that we use the enforced separation approach of Example 10.7. Thus, we first solve the jobs-tomachines 2-dimensional assignment problem with values.
Example 10.7In the assignment problems we have considered so far, we group the nodes of the graph in pairs. Multidimensional assignment problems involve the grouping of the nodes in subsets with more than two elements, such as triplets or quadruplets of nodes. For an example of a 3-dimensional assignment problem, suppose that the performance of a job j requires a machine m and a worker w, and that there is a given value ajmw corresponding to the triplet (j, m,w). Given a set of jobs J, a set of machines M, and a set of workers W, we want to find a collection of job/machine/worker triplets that has maximum total value.