16.2 Efficiency in Exchange ▣Exchange economy(佼换经济)-Market in which two or more consumers trade two goods among themselves. Efficient allocation-Allocation of goods in which no one can be made better off unless someone else is made worse off. 口Edgeworth box(埃奇沃斯盒形-Diagram(际圈)showing all possible allocations of either two goods between two people or of two inputs between two production processes.16.2 Efficiency in Exchange  Exchange economy(交换经济)-Market in which two or more consumers trade two goods among themselves.  Efficient allocation-Allocation of goods in which no one can be made better off unless someone else is made worse off.  Edgeworth box (埃奇沃斯盒形图)-Diagram (示图) showing all possible allocations of either two goods between two people or of two inputs between two production processes