Stability of the feasible set in balanced transportation problems

In this paper we study the stability of the feasible set of a balanced transportation problem. A transportation problem is balanced when the total supply is equal to the total demand. One can easily see that when we make minor adjustments to the data (supply and demand), the resulting problem may lose the property of balance. Therefore, although the transportation problem is a particular case of linear programming, you cannot apply the familiar results of stability. For a fixed number of origins and destinations we have obtained a vector representation for any feasible solution of the transportation problem. We have used this representation to prove that the feasible set mapping is continuous. We have also proved that the extreme point set mapping is lower semi continuous.