I was thinking that the structure theorem for abelian groups is not true for the trivial group. Am I missing something or is the theorem just valid for groups of order $>{1}$ ?
Edit: The theorem I'm working with is: Let $G$ be an abelian group of finite order, then there exist integers $d_1,...,d_k$ so that $$G\sim\Bbb{Z}/(d_1)\times...\times\Bbb{Z}/(d_k),$$ and so that $d_i\mid{d_{i+1}}$ for $1\leq{i}\leq{k-1}$. The trivial group clearly doesn't satisfy this.