We describe the split extension classifiers in the semi-abelian category of cocommutative Hopf algebras over an algebraically closed field of characteristic zero. The categorical notions of centralizer and of center in the category of cocommutative Hopf algebras is then explored. We show that the categorical notion of center coincides with the one that is considered in the theory of general Hopf algebras.
"Split extension classifiers in the category of cocommutative Hopf algebras." Bull. Belg. Math. Soc. Simon Stevin 25 (3) 355 - 382, september 2018. https://doi.org/10.36045/bbms/1536631232