In this paper, the question of when the subdirect sum of matrices is in the class of matrices is studied. Some sufficient conditions are given. Moreover, these sufficient conditions only depend on the elements of given matrices; thus, they provide some simple criteria for application. Numerical examples are also presented to illustrate the corresponding results.

中文翻译：

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矩阵的子直接和

本文研究了矩阵的子直接和何时属于矩阵类的问题。给出了一些充分的条件。而且，这些足够的条件仅取决于给定矩阵的元素。因此，它们提供了一些简单的应用标准。还提供了数值示例来说明相应的结果。