In this paper, we consider the existence of extremal solutions for a type of fractional compartment models. By use of a new comparison result, some new sufficient conditions for the existence of solutions are established by combining the monotone iterative technique and the methods of lower and upper solutions. Finally, an example is presented to illustrate the validity of our main results.

中文翻译：

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分数区间模型的极值解的存在

在本文中，我们考虑了一类分数区间模型的极值解的存在。利用新的比较结果，通过将单调迭代技术与上下解方法相结合，为解的存在建立了一些新的充分条件。最后，通过一个例子来说明我们主要结果的有效性。