In this paper, a multistage decision-making problem concerning uncertainty and ambiguity is discussed using Pythagorean fuzzy sets. Complement Pythagorean fuzzy membership grades and their properties are also considered. Using the definition of an alpha-level set, we introduce the multistage decision-making problems, where the possibility theory and satisfaction grades are declared with the help of Pythagorean membership grades. Pythagorean multistage decision-making is an uncertain theory, where decision-maker has only one opportunity to choose the scenario under the combination of Pythagorean possibility and satisfaction grades at each stage. According to the selection of criteria, a series of decision points are concluded. The payoff collaborates with these decision points at each stage. The multistage decision-making using Pythagorean fuzzy sets is the scenario-based theory in place of other theories like lottery-based theory etc. The results have been calculated using multistage Pythagorean fuzzy sets in which the decision-maker has only one chance to select the optimal solution. The TOPSIS technique has been applied and the comparison between these two techniques is highlighted.

中文翻译：

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毕达哥拉斯模糊集的短生命周期产品多阶段决策方法

本文利用毕达哥拉斯模糊集讨论了关于不确定性和歧义性的多阶段决策问题。还考虑了互补毕达哥拉斯模糊隶属度等级及其性质。使用alpha水平集的定义，我们介绍了多阶段决策问题，其中通过毕达哥拉斯（Pythagorean）隶属度等级来声明可能性理论和满意度等级。毕达哥拉斯的多阶段决策是一种不确定的理论，决策者只有一个机会根据毕达哥拉斯的可能性和满意度在每个阶段的组合来选择情景。根据选择的标准，得出了一系列决策点。收益在每个阶段都与这些决策点协作。使用毕达哥拉斯模糊集的多阶段决策是基于场景的理论，代替了诸如彩票理论等其他理论。结果是使用多阶段毕达哥拉斯模糊集来计算的，其中决策者只有一次选择机会。最佳解决方案。TOPSIS技术已被应用，并且突出了这两种技术之间的比较。