Then, the follows are gotten: the existence of Jordan form main matrices which are similar to a square matrix, and a necessary and sufficient condition of a matrix similar to a diagonal matrix, and the real coefficient minimum polynomial of a matrix.

• 用之导出四元数方阵所相似的Jordan形主矩阵的唯一性，四元数矩阵相似于对角形矩阵的一个充要条件及四元数方阵的最小实系数零化多项式的形式。