Consider an economy of three-period-lived people in overlapping generations. Each person is endowed with y goods when young and old and nothing when middle-aged. The population of each generation born in period t is N_t, where N_t = nN_t-1. There are no assets other than loans. Explain how  credit can be used to provide for consumption when middle-aged. Point out who lends to whom and write the condition for the equality of supply and demand for loans in period . Write the budget constraints for the young, the middle-aged, and the old. Be sure to define any notation you introduce.