A company has decided to use 01 integer programming to help make some investment decisions. There are three possible investment alternatives from which to choose, but if it is decided that a particular alternative is to be selected, the entire cost of that alternative will be incurred (i.e., it is impossible to build one-half of a factory). The integer programming model is as follows: Maximize Subject to: Constraint 1 Constraint 2 5000 X1 + 7000X2 + 9000X3 X1 + X2 + X3 2 -X1 + X2 so 25,000 X1 + 32,000 X2 + 29,000 X3 s 62,000 16 X1 + 14 X2 + 19 X3 = 36 all variables = 0 or 1 (budget limit) (resource limitation) where X1 = 1 if alternative 1 is selected, 0 otherwise X2 = 1 if alternative 2 is selected, 0 otherwise X3 = 1 if alternative 3 is selected, 0 otherwise Solution x1 = 1, X2 = 0, X3 = 1, objective value = 14,000. Table 10-3 presents an integer programming problem. Suppose you wish to add a constraint that stipulates that both alternative 2 and alternative 3 must be selected, or neither can be selected. How would this constraint be written? X2 s X3 X2 = X3 X2 2 X3 X2 + X3 = 1