Period Three Implies Chaos

  title={Period Three Implies Chaos},
  author={Tien-Yien Li and James A. Yorke},
  journal={American Mathematical Monthly},
The way phenomena or processes evolve or change in time is often described by differential equations or difference equations. One of the simplest mathematical situations occurs when the phenomenon can be described by a single number as, for example, when the number of children susceptible to some disease at the beginning of a school year can be estimated purely as a function of the number for the previous year. That is, when the number x n+1, at the beginning of the n + 1st year (or time period… 

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