Let be a hypergroup and consider on the relations defined by: if and only if and if then if and only if there exists such that and are in . The relation is an equivalence relation on , it is strongly regular and is a group [see P. Corsini, Prolegomena of Hypergroup Theory. (1993; Zbl 0785.20032)]. If 1 is the identity of the group and is the canonical projection then is called the heart of .
The purpose of this paper is to characterize the hypergroups for which the heart is a hyperproduct, i.e. there exist and such that .