通过代数和数论的方法,研究了Z-模范畴中Zn的拉回,给出了具体的描述,并利用该结果给出了一类构造关于欧拉函数等式的方法。
The fibre product of Zn in the category of Z-modules is described with the methods of algebra and number theory. The results also apply a way to construct the equalities of Euler function φ(n).