Fold a piece of squared paper along the diagonal into a triangle, and fold into another triangle.

把一张正方形的纸沿着对角线折成三角形，然后再对折一次。

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This paper defined up-triangle equal minor diagonal matrix and up-triangle stagger minor diagonal matrix.

定义了上三角等次对角线矩阵和上三角交错次对角线矩阵；

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This paper defined up-triangle equal minor diagonal matrix and up-triangle stagger minor diagonal matrix.

定义了上三角等次对角线矩阵和上三角交错次对角线矩阵；

youdao