(* This program is free software; you can redistribute it and/or      *)
(* modify it under the terms of the GNU Lesser General Public License *)
(* as published by the Free Software Foundation; either version 2.1   *)
(* of the License, or (at your option) any later version.             *)
(*                                                                    *)
(* This program is distributed in the hope that it will be useful,    *)
(* but WITHOUT ANY WARRANTY; without even the implied warranty of     *)
(* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the      *)
(* GNU General Public License for more details.                       *)
(*                                                                    *)
(* You should have received a copy of the GNU Lesser General Public   *)
(* License along with this program; if not, write to the Free         *)
(* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA *)
(* 02110-1301 USA                                                     *)
Set Implicit Arguments.
Unset Strict Implicit.
Require Export Group_kernel.
(** Title "Factorisation of a group homomorphism: G -> G/Kerf -> coKerf -> G'." *)
Section Def.
Variable G G' : GROUP.
Variable f : Hom G G'.
Definition surj_group_quo_ker :
Hom G (group_quo G (Ker f) (kernel_normal (G:=G) (G':=G') (f:=f))) :=
group_quo_surj (kernel_normal (f:=f)).

Lemma surj_group_quo_ker_surjective : surjective surj_group_quo_ker.
red in |- *.