{A B C : Group} {i : A $-> B} {f : B $-> C} `{IsEmbedding i} (ex : IsExact (Tr (-1)) i f) : GroupIsomorphism A (grp_kernel f) := Build_GroupIsomorphism _ _ (grp_cxfib cx_isexact) (isequiv_cxfib ex).
Require Import Basics Types. Require Import Truncations.Core. Require Import WildCat.Core Pointed. Require Import Groups.Group Groups.Subgroup Groups.Kernel. Require Import Homotopy.ExactSequence Modalities.Identity.