On Nonlinear Dynamics: The Case of the Pork Cycle
用新方法分析猪粮比价，发现猪周期存在非线性动态，GARCH模型只能解释部分非线性，且可能存在混沌现象，说明猪周期不能用少数状态变量充分刻画。
Abstract New methods for analyzing nonlinear dynamic processes are used to evaluate the hogcorn price ratio. The results present evidence of nonlinear dynamics in the pork cycle. Moreover, while GARCH processes account for some of the nonlinearities, the pork cycle is apparently characterized by more complex dynamic forms. The empirical analysis provides some evidence of the presence of chaos in the pork cycle. The results also indicate that the dynamic process generating the pork cycle is nonlinear and cannot be adequately characterized by a small number of state variables.