Revisiting the fixed charge transportation problem
Résumé
We analyze degeneracy characterizations for two classical problems: the transportation paradox in linear transportation problems and the pure fixed charge transportation problem. Solving the pure constant fixed charge problem is equivalent to finding a basic tree solution with maximum degree of degeneracy. Problems possess degenerate solutions if the equal subsum property is satisfied for the supplies and demands. To determine the existence of degeneracy is an NP-complete problem. But this NP-hardness remains even if all equal-subsums are known in advance. Finally, the paradox is linked to overshipment solutions, which belong to supply and demand configurations that tend to have a high degree of degeneracy.