Hypergroups of compact type

摘要

We consider commutative hypergroups with translation operators which are compact on L2 resp. L1. It will be shown that such hypergroups are necessarily discrete and that in the case of compact translations on L1 the support of the Plancherel measure coincides with the set of all characters and the hypergroup must be symmetric. Furthermore we will show that a certain type of Reiter's condition is fulfilled.