Efficient Pareto-improving Processes

We give two procedures for determining whether efficient Pareto improving local changes are possible. When they are, the procedures compute for them. Any procedure generating efficient and Pareto improving changes can be replicated by these procedures. The two programs form a striking duality. We apply the procedures to Pareto improving exchange processes, Pareto-improving tariff-tax reforms and to the problem of constrained Pareto optimum where informational constraints are present.