Regularity of the category of commutative Hopf algebras
Ascertain whether the category of commutative Hopf algebras over a field is regular in the sense of Barr (equivalently, whether it is Barr-exact).
References
Cocommutative Hopf algebras over a field form a semiabelian category [40,38], while commutative Hopf algebras are at least homologically self-dual (see Example 2.5.16; they are co-protomodular by [36], but regularity is currently not clear).
                — A Homological View of Categorical Algebra
                
                (2404.15896 - Peschke et al., 24 Apr 2024) in An overview of exactness conditions and categorical structures (Introductory summary, early Part I)