rewrite < (e_is_left_unit ? G);
rewrite < (e_is_left_unit ? G z);
rewrite < (inv_is_left_inverse ? G x);
-rewrite > (associative ? (is_semi_group ? ( G)));
-rewrite > (associative ? (is_semi_group ? ( G)));
+rewrite > (op_associative ? G);
+rewrite > (op_associative ? G);
apply eq_f;
assumption.
qed.
unfold injective;
simplify;fold simplify (op G);
intros (x y z);
-rewrite < (e_is_right_unit ? ( G));
-rewrite < (e_is_right_unit ? ( G) z);
+rewrite < (e_is_right_unit ? G);
+rewrite < (e_is_right_unit ? G z);
rewrite < (inv_is_right_inverse ? G x);
-rewrite < (associative ? (is_semi_group ? ( G)));
-rewrite < (associative ? (is_semi_group ? ( G)));
+rewrite < (op_associative ? G);
+rewrite < (op_associative ? G);
rewrite > H;
reflexivity.
qed.
-theorem inv_inv: ∀G:Group. ∀x:G. x \sup -1 \sup -1 = x.
+theorem eq_inv_inv_x_x: ∀G:Group. ∀x:G. x \sup -1 \sup -1 = x.
intros;
apply (eq_op_x_y_op_z_y_to_eq ? (x \sup -1));
rewrite > (inv_is_right_inverse ? G);
∀G:Group. ∀x,y,z:G. x·y=z → x = z·y \sup -1.
intros;
apply (eq_op_x_y_op_z_y_to_eq ? y);
-rewrite > (associative ? G);
+rewrite > (op_associative ? G);
rewrite > (inv_is_left_inverse ? G);
rewrite > (e_is_right_unit ? G);
assumption.
∀G:Group. ∀x,y,z:G. x·y=z → y = x \sup -1·z.
intros;
apply (eq_op_x_y_op_x_z_to_eq ? x);
-rewrite < (associative ? G);
+rewrite < (op_associative ? G);
rewrite > (inv_is_right_inverse ? G);
-rewrite > (e_is_left_unit ? (is_monoid ? G));
+rewrite > (e_is_left_unit ? G);
assumption.
qed.
intros;
apply (eq_op_x_y_op_z_y_to_eq ? (x·y));
rewrite > (inv_is_left_inverse ? G);
-rewrite < (associative ? G);
-rewrite > (associative ? G (y \sup -1));
+rewrite < (op_associative ? G);
+rewrite > (op_associative ? G (y \sup -1));
rewrite > (inv_is_left_inverse ? G);
rewrite > (e_is_right_unit ? G);
rewrite > (inv_is_left_inverse ? G);
theorem morphism_to_eq_f_1_1:
∀G,G'.∀f:morphism G G'.f˜1 = 1.
intros;
-apply (eq_op_x_y_op_z_y_to_eq G' (f˜1));
-rewrite > (e_is_left_unit ? G' ?);
-rewrite < (f_morph ? ? f);
+apply (eq_op_x_y_op_z_y_to_eq ? (f˜1));
+rewrite > (e_is_left_unit ? G');
+rewrite < f_morph;
rewrite > (e_is_left_unit ? G);
reflexivity.
qed.
∀G,G'.∀f:morphism G G'.
∀x.f˜(x \sup -1) = (f˜x) \sup -1.
intros;
-apply (eq_op_x_y_op_z_y_to_eq G' (f˜x));
+apply (eq_op_x_y_op_z_y_to_eq ? (f˜x));
rewrite > (inv_is_left_inverse ? G');
-rewrite < (f_morph ? ? f);
+rewrite < f_morph;
rewrite > (inv_is_left_inverse ? G);
apply (morphism_to_eq_f_1_1 ? ? f).
qed.
(* Subgroups *)
record subgroup (G:Group) : Type ≝
- { group: Group;
+ { group:> Group;
embed:> monomorphism group G
}.
+
+notation < "G"
+for @{ 'type_of_subgroup $G }.
+
+interpretation "Type_of_subgroup coercion" 'type_of_subgroup G =
+ (cic:/matita/algebra/groups/Type_of_subgroup.con _ G).
notation "hvbox(x \sub H)" with precedence 79
for @{ 'subgroupimage $H $x }.
unfold left_coset_eq;
simplify in ⊢ (? → ? ? ? (? ? % ?));
simplify in ⊢ (? → ? ? ? (? ? ? (? ? ? (? ? %) ?)));
-simplify in ⊢ (? % → ?);
+simplify in ⊢ (? ? % → ?);
intros;
unfold member_of_left_coset;
simplify in ⊢ (? ? (λy:?.? ? ? (? ? ? (? ? ? (? ? %) ?))));
-simplify in ⊢ (? ? (λy:? %.?));
+simplify in ⊢ (? ? (λy:? ? %.?));
simplify in ⊢ (? ? (λy:?.? ? ? (? ? % ?)));
unfold member_of_subgroup in H1;
elim H1;
clear H1;
exists;
[ apply (a\sup-1 · x1)
-| rewrite > (f_morph ? ? (morphism ? ? H));
- rewrite > (eq_image_inv_inv_image ? ?
+| rewrite > f_morph;
+ rewrite > eq_image_inv_inv_image;
rewrite < H2;
- rewrite > (eq_inv_op_x_y_op_inv_y_inv_x ? ? ? ? H2);
+ rewrite > eq_inv_op_x_y_op_inv_y_inv_x;
+ rewrite > eq_inv_inv_x_x;
+ rewrite < (op_associative ? G);
+ rewrite < (op_associative ? G);
+ rewrite > (inv_is_right_inverse ? G);
+ rewrite > (e_is_left_unit ? G);
+ reflexivity
].
qed.