Cocommuative Hopf algebras over \(\mathbb{Z}\)
We describe cocommutative Hopf algebras over \(\mathbb{Z}\), which are free \(\mathbb{Z}\)-modules of square-free odd rank, and also present some examples of Hopf algebras over \(\mathbb{Q}\) in which no Hopf \(\mathbb{Z}\)-orders exist.
scientific article; zbMATH DE number 1028400