A universal algebraic approach to rack coverings

We study rack and quandle coverings from a universal algebraic viewpoint. We show how coverings can be understood using the concept of strongly abelian congruences. We provide an abstract characterization of several particular types of covering extensions, such as central and abelian ones. We present a new characterization of simply connected quandles and we show that the categorical notion of normal extension coincides with the notion of central covering. We answer several questions from the papers of Clark, Saito and Vendramin about identities preserved by quandle coverings.