We obtain sufficient conditions for the weak persistence of prey-predator systems by construct persistent functions. 通过构造持久性函数得到了系统弱持续生存的充分条件。
In a functional programming language, persistent data structures are also important for writing pure functions, free of side-effects. 在函数式编程语言中,持久数据结构对于编写纯粹的函数(无负面作用)的意义也是十分重要的。