Section Lemmas.
Variable G : GROUP.
intros n g; try assumption.
apply Trans with (Ap (sgroup_map (monoid_sgroup_hom (Z_to_group_nat g))) n);
auto with algebra.
apply Sym.
apply Z_to_group_fun_eq.
Qed.
Hint Resolve Z_to_group_nat_eq_pos: algebra.
simple induction n.
intros H'; try assumption.
inversion H'.
intros p H'; try assumption.
replace 0%Z with (- (0))%Z.
apply Z.lt_gt; auto with algebra.
auto with algebra.
intros p H'; try assumption.
replace 0%Z with (- (0))%Z.
apply Z.lt_gt; auto with algebra.
auto with algebra.
Qed.
Hint Resolve Zopp1: algebra.
simple induction n.
intros H'; try assumption.
inversion H'.
intros p H'; try assumption.
replace 0%Z with (- (0))%Z.
apply Z.gt_lt; auto with algebra.
auto with algebra.
intros p H'; try assumption.
replace 0%Z with (- (0))%Z.
apply Z.gt_lt; auto with algebra.
auto with algebra.
Qed.
Hint Resolve Zopp2: algebra.
intros x; try assumption.
elim x.
intros p p'; try assumption.
red in p'.
inversion p.
intros p p0 p'; simpl in |- *.
auto with algebra.
intros p p0 p'; try assumption.
red in p'.
simpl in p'.
inversion p'.
Qed.
Hint Resolve Zl2 Zl1 Zl3 nat_to_group_inverse: algebra.

Lemma nat_to_group_comp :
forall (r r' : G) (n : nat),
Equal r r' -> Equal (nat_to_group r n) (nat_to_group r' n).