End AbelianStructure.
Arguments abelian_type {gT} A%g.
Arguments homocyclic {gT} A%g.
Section IsogAbelian.
Variables aT rT : finGroupType.
Implicit Type (gT : finGroupType) (D G : {group aT}) (H : {group rT}).

Lemma isog_abelian_type G H : isog G H -> abelian_type G = abelian_type H.