Note—Rolling Back Decision Trees Requires the Independence Axiom!
证明Herstein-Milnor独立性公理是扩展式（树形）决策递归分析的必要条件，对研究决策树滚动回退方法的学者有参考价值。
The Herstein–Milnor independence axiom is a necessary condition for recursion analysis of decisions in extensive (=tree) form.