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(* 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.             *)
(*                                                                    *)
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(* 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 Field_cat.
Require Export Ring_facts.
(** Title "Basic properties of fields." *)
Section Lemmas1.
Variable K : FIELD.
Definition field_inverse (x : K) : K := Ap (field_inverse_map K) x.
Definition field_div (x y : K) : K := ring_mult x (field_inverse y).

(* Specifications: *)
Lemma FIELD_inverse_r :
forall x : K,
~ Equal x (monoid_unit K) ->
Equal (ring_mult x (field_inverse x)) (ring_unit K).