The arithmetic operations given between the Interval Type-2 Trapezoidal Fuzzy Numbers (IT2TrFN)s should satisfy the closeness property. Otherwise, the result encountered when the operations are used may be meaningless and not suitable for the purpose. The aim of this note is to show errors in the definitions using a non-closed division operation given by paper Pan and Wang (Int J Fuzzy Syst 144:1–15, 2020).

中文翻译：

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关于模糊余弦函数的一个注记

区间类型 2 梯形模糊数 (IT2TrFN) 之间给出的算术运算应满足接近性。否则，使用操作时遇到的结果可能毫无意义，不适合该目的。本笔记的目的是使用 Pan 和 Wang (Int J Fuzzy Syst 144:1–15, 2020) 给出的非封闭除法运算来显示定义中的错误。