The number of subgroups of the group ${\mathbb{Z}}_m\times {\mathbb{Z}}_n\times {\mathbb{Z}}_r\times {\mathbb{Z}}_s$

László Tóth

We deduce direct formulas for the total number of subgroups and the number of subgroups of a given order of the group ${\mathbb{Z}}_m\times {\mathbb{Z}}_n\times {\mathbb{Z}}_r\times {\mathbb{Z}}_s$,…