fact: Definition abgroup_first_iso `{Funext} {A B : AbGroup} (f : A $-> B) : GroupIsomorphism (QuotientAbGroup A (grp_kernel f)) (abgroup_image f).
imports: Basics Types Classes.interfaces.canonical_names (Zero, zero) Classes.interfaces.abstract_algebra (IsAbGroup(..), abgroup_group, abgroup_commutative) Algebra.Groups.Group Algebra.Groups.Subgroup Algebra.Groups.QuotientGroup WildCat