See also the following links:

▎ENGLISH

Decision Tree Algorithm, Explained
▸ https://www.kdnuggets.com/2020/01/decision-tree-algorithm-explained.html

What is decision tree pruning and how is it done?
▸ https://www.educative.io/edpresso/what-is-decision-tree-pruning-and-how-is-it-done

▎日 本 語

決定木分析についてざっくりまとめ_理論編
▸ https://dev.classmethod.jp/articles/2017ad_20171211_dt-2/

決定木分析とは？（手法解析から注意点まで）
▸ https://surveroid.jp/mr-journal/terms/Atckv