Abstract A closed-form expression for the remaining life expectancy based on the gamma-Gompertz model has been derived recently in the literature. However, the closed-form expression available to users is not correct. We provide, therefore, a valid and correct expression for the life expectancy at age x by using elementary calculus. We also consider a comparative numerical study by using real data to confirm that the formula we provide works properly.

中文翻译：

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关于伽马-Gompertz 预期寿命

摘要 最近，文献中提出了基于 gamma-Gompertz 模型的剩余预期寿命的闭式表达式。但是，用户可用的封闭式表达式是不正确的。因此，我们通过使用初等微积分为 x 岁的预期寿命提供了一个有效且正确的表达式。我们还考虑使用真实数据进行比较数值研究，以确认我们提供的公式是否正常工作。