This commit is contained in:
Thomas Baruchel 2023-01-15 15:23:55 +01:00
parent de483aef11
commit 03eed617c7

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@ -629,6 +629,7 @@ Proof.
destruct M as [hd'' M2]. destruct M2 as [a'' M3]. destruct M3 as [tl'' M].
destruct L as [L1 L2]. destruct L2 as [L2 L3].
destruct M as [M1 M2]. destruct M2 as [M2 M3].
assert (L0 := L1). assert (M0 := M1).
assert (N: 0 < n).
generalize K. generalize I. generalize H. apply tm_step_not_nil_factor_even.
@ -690,42 +691,231 @@ Proof.
rewrite <- tm_morphism_app in M1. rewrite <- tm_morphism_app in M1.
rewrite <- tm_morphism_app in M1. rewrite <- tm_morphism_eq in M1.
assert (Nat.Even (Nat.div2 (length hd')) \/ Nat.Odd (Nat.div2 (length hd'))).
apply Nat.Even_or_Odd. destruct H0.
(* now we easily discard the case where a'0 would be odd since we
can freely choose either L1 or M1 to find an even prefix *)
assert (Nat.Even (Nat.div2 (length a)) \/ Nat.Odd (Nat.div2 (length a))).
apply Nat.Even_or_Odd. destruct H0 as [Z | Z].
- (* first case, a'0 is even and we are looking for an odd prefix *)
assert (Nat.Even (Nat.div2 (length hd')) \/ Nat.Odd (Nat.div2 (length hd'))).
apply Nat.Even_or_Odd. destruct H0.
(* case Nat.div2 (length hd'') has an odd length *)
- assert( odd (Nat.div2 (length hd'')) = true).
apply eq_S in M2. rewrite Nat.succ_pred_pos in M2.
apply eq_S in M2. rewrite <- L2 in M2. rewrite <- M2 in H0.
+ (* case Nat.div2 (length hd'') has an odd length *)
exists (firstn (Nat.div2 (length hd'')) (tm_step n)).
exists (firstn (Nat.div2 (length a''))
(skipn (Nat.div2 (length hd'')) (tm_step n))).
exists (skipn (Nat.div2 (length (a'' ++ a'')))
(skipn (Nat.div2 (length hd'')) (tm_step n))
++ map negb (tm_step n)).
split. rewrite tm_build. rewrite M1 at 1.
rewrite <- app_assoc. rewrite <- app_assoc.
rewrite <- app_assoc. reflexivity.
assert (Nat.div2 (length hd'') <= length (tm_step n)).
rewrite Nat.mul_le_mono_pos_l with (p := 2).
rewrite <- Nat.double_twice. rewrite <- Nat.Even_double.
rewrite tm_size_power2. rewrite <- Nat.pow_succ_r'.
rewrite <- tm_size_power2. rewrite M0.
rewrite app_length. rewrite <- Nat.add_0_r at 1.
apply Nat.add_le_mono. apply Nat.eq_le_incl. reflexivity.
apply le_0_n. apply Nat.EvenT_Even. apply Nat.even_EvenT.
assumption. apply Nat.lt_0_2.
split.
rewrite firstn_length_le.
apply eq_S in M2. rewrite Nat.succ_pred_pos in M2.
apply eq_S in M2. rewrite <- L2 in M2. rewrite <- M2 in H0.
rewrite <- Nat.Odd_div2 in H0. rewrite <- Nat.Even_div2 in H0.
apply Nat.Even_succ in H0. apply Nat.Odd_OddT in H0.
apply Nat.OddT_odd in H0. apply H0.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.OddT_Odd. apply Nat.odd_OddT. rewrite Nat.odd_succ.
assumption.
destruct (length hd). inversion J. apply Nat.lt_0_succ.
assumption.
split. rewrite firstn_length_le.
rewrite M3. apply Nat.EvenT_even. apply Nat.Even_EvenT.
assumption. rewrite skipn_length.
rewrite Nat.add_le_mono_l with (p := Nat.div2 (length hd'')).
rewrite Nat.add_sub_assoc. rewrite Nat.add_sub_swap.
rewrite Nat.sub_diag. rewrite Nat.add_0_l.
rewrite Nat.mul_le_mono_pos_l with (p := 2).
rewrite tm_size_power2. rewrite Nat.mul_add_distr_l.
rewrite <- Nat.double_twice. rewrite <- Nat.double_twice.
rewrite <- Nat.Even_double. rewrite <- Nat.Even_double.
rewrite <- Nat.pow_succ_r'. rewrite <- tm_size_power2. rewrite M0.
rewrite app_assoc. rewrite app_length. rewrite <- Nat.add_0_r at 1.
apply Nat.add_le_mono. rewrite app_length. apply Nat.eq_le_incl.
reflexivity.
apply le_0_n.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.lt_0_2. apply Nat.eq_le_incl. reflexivity.
assumption.
rewrite firstn_length.
assert (min (Nat.div2 (length a''))
(length (skipn (Nat.div2 (length hd'')) (tm_step n)))
<= (Nat.div2 (length a''))).
apply Nat.le_min_l.
assert (Nat.div2 (length a'') < length a). rewrite M3.
apply Nat.lt_div2. assumption.
generalize H3. generalize H2. apply Nat.le_lt_trans.
+ (* case Nat.div2 (length hd') has an odd length *)
exists (firstn (Nat.div2 (length hd')) (tm_step n)).
exists (firstn (Nat.div2 (length a'))
(skipn (Nat.div2 (length hd')) (tm_step n))).
exists (skipn (Nat.div2 (length (a' ++ a')))
(skipn (Nat.div2 (length hd')) (tm_step n))
++ map negb (tm_step n)).
split. rewrite tm_build. rewrite L1 at 1.
rewrite <- app_assoc. rewrite <- app_assoc.
rewrite <- app_assoc. reflexivity.
assert (Nat.div2 (length hd') <= length (tm_step n)).
rewrite Nat.mul_le_mono_pos_l with (p := 2).
rewrite <- Nat.double_twice. rewrite <- Nat.Even_double.
rewrite tm_size_power2. rewrite <- Nat.pow_succ_r'.
rewrite <- tm_size_power2. rewrite L0.
rewrite app_length. rewrite <- Nat.add_0_r at 1.
apply Nat.add_le_mono. apply Nat.eq_le_incl. reflexivity.
apply le_0_n. apply Nat.EvenT_Even. apply Nat.even_EvenT.
assumption. apply Nat.lt_0_2.
split.
rewrite firstn_length_le.
apply Nat.OddT_odd. apply Nat.Odd_OddT. assumption.
assumption.
split. rewrite firstn_length_le.
rewrite L3. apply Nat.EvenT_even. apply Nat.Even_EvenT.
assumption. rewrite skipn_length.
rewrite Nat.add_le_mono_l with (p := Nat.div2 (length hd')).
rewrite Nat.add_sub_assoc. rewrite Nat.add_sub_swap.
rewrite Nat.sub_diag. rewrite Nat.add_0_l.
rewrite Nat.mul_le_mono_pos_l with (p := 2).
rewrite tm_size_power2. rewrite Nat.mul_add_distr_l.
rewrite <- Nat.double_twice. rewrite <- Nat.double_twice.
rewrite <- Nat.Even_double. rewrite <- Nat.Even_double.
rewrite <- Nat.pow_succ_r'. rewrite <- tm_size_power2. rewrite L0.
rewrite app_assoc. rewrite app_length. rewrite <- Nat.add_0_r at 1.
apply Nat.add_le_mono. rewrite app_length. apply Nat.eq_le_incl.
reflexivity.
apply le_0_n.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.lt_0_2. apply Nat.eq_le_incl. reflexivity.
assumption.
rewrite firstn_length.
assert (min (Nat.div2 (length a'))
(length (skipn (Nat.div2 (length hd')) (tm_step n)))
<= (Nat.div2 (length a'))).
apply Nat.le_min_l.
assert (Nat.div2 (length a') < length a). rewrite L3.
apply Nat.lt_div2. assumption.
generalize H3. generalize H2. apply Nat.le_lt_trans.
- (* second case, a'0 is odd and we are looking for an even prefix *)
assert (Nat.Even (Nat.div2 (length hd')) \/ Nat.Odd (Nat.div2 (length hd'))).
apply Nat.Even_or_Odd. destruct H0.
+ assert (Nat.div2 (length hd') <= length (tm_step n)).
rewrite Nat.mul_le_mono_pos_l with (p := 2).
rewrite <- Nat.double_twice. rewrite <- Nat.Even_double.
rewrite tm_size_power2. rewrite <- Nat.pow_succ_r'.
rewrite <- tm_size_power2. rewrite L0.
rewrite app_length. rewrite <- Nat.add_0_r at 1.
apply Nat.add_le_mono. apply Nat.eq_le_incl. reflexivity.
apply le_0_n. apply Nat.EvenT_Even. apply Nat.even_EvenT.
assumption. apply Nat.lt_0_2.
assert (even (length (firstn (Nat.div2 (length hd')) (tm_step n))) = false).
assert (odd (length (firstn (Nat.div2 (length a'))
(skipn (Nat.div2 (length hd')) (tm_step n)))) = true).
rewrite firstn_length_le. rewrite L3.
apply Nat.OddT_odd. apply Nat.Odd_OddT. assumption.
rewrite skipn_length.
rewrite Nat.add_le_mono_l with (p := Nat.div2 (length hd')).
rewrite Nat.add_sub_assoc. rewrite Nat.add_sub_swap.
rewrite Nat.sub_diag. rewrite Nat.add_0_l.
rewrite Nat.mul_le_mono_pos_l with (p := 2).
rewrite tm_size_power2. rewrite Nat.mul_add_distr_l.
rewrite <- Nat.double_twice. rewrite <- Nat.double_twice.
rewrite <- Nat.Even_double. rewrite <- Nat.Even_double.
rewrite <- Nat.pow_succ_r'. rewrite <- tm_size_power2. rewrite L0.
rewrite app_assoc. rewrite app_length. rewrite <- Nat.add_0_r at 1.
apply Nat.add_le_mono. rewrite app_length. apply Nat.eq_le_incl.
reflexivity.
apply le_0_n.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.lt_0_2. apply Nat.eq_le_incl. reflexivity.
assumption.
generalize H2. generalize L1. apply tm_step_odd_prefix_square.
rewrite firstn_length_le in H2.
apply Nat.Even_EvenT in H0. apply Nat.EvenT_even in H0.
rewrite H0 in H2. inversion H2. assumption.
+ assert (Nat.div2 (length hd'') <= length (tm_step n)).
rewrite Nat.mul_le_mono_pos_l with (p := 2).
rewrite <- Nat.double_twice. rewrite <- Nat.Even_double.
rewrite tm_size_power2. rewrite <- Nat.pow_succ_r'.
rewrite <- tm_size_power2. rewrite M0.
rewrite app_length. rewrite <- Nat.add_0_r at 1.
apply Nat.add_le_mono. apply Nat.eq_le_incl. reflexivity.
apply le_0_n. apply Nat.EvenT_Even. apply Nat.even_EvenT.
assumption. apply Nat.lt_0_2.
assert (even (length (firstn (Nat.div2 (length hd'')) (tm_step n))) = false).
assert (odd (length (firstn (Nat.div2 (length a''))
(skipn (Nat.div2 (length hd'')) (tm_step n)))) = true).
rewrite firstn_length_le. rewrite M3.
apply Nat.OddT_odd. apply Nat.Odd_OddT. assumption.
rewrite skipn_length.
rewrite Nat.add_le_mono_l with (p := Nat.div2 (length hd'')).
rewrite Nat.add_sub_assoc. rewrite Nat.add_sub_swap.
rewrite Nat.sub_diag. rewrite Nat.add_0_l.
rewrite Nat.mul_le_mono_pos_l with (p := 2).
rewrite tm_size_power2. rewrite Nat.mul_add_distr_l.
rewrite <- Nat.double_twice. rewrite <- Nat.double_twice.
rewrite <- Nat.Even_double. rewrite <- Nat.Even_double.
rewrite <- Nat.pow_succ_r'. rewrite <- tm_size_power2. rewrite M0.
rewrite app_assoc. rewrite app_length. rewrite <- Nat.add_0_r at 1.
apply Nat.add_le_mono. rewrite app_length. apply Nat.eq_le_incl.
reflexivity.
apply le_0_n.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.lt_0_2. apply Nat.eq_le_incl. reflexivity.
assumption.
generalize H2. generalize M1. apply tm_step_odd_prefix_square.
rewrite firstn_length_le in H2.
(*
assert (L9: a' ++ a' = a' ++ a'). reflexivity.
rewrite L8 in L9 at 4. rewrite L8 in L9 at 3.
rewrite <- tm_morphism_app in L9.
assert (M9: a'' ++ a'' = a'' ++ a''). reflexivity.
rewrite M8 in M9 at 4. rewrite M8 in M9 at 3.
rewrite <- tm_morphism_app in M9.
*)
tm_morphism_app2:
forall l hd tl : list bool,
tm_morphism l = hd ++ tl ->
even (length hd) = true ->
hd = tm_morphism (firstn (Nat.div2 (length hd)) l)
Lemma tm_morphism_app3 : forall (l hd tl : list bool),
tm_morphism l = hd ++ tl
-> even (length hd) = true
-> tl = tm_morphism (skipn (Nat.div2 (length hd)) l).
apply eq_S in M2. rewrite Nat.succ_pred_pos in M2.
apply eq_S in M2. rewrite <- L2 in M2. rewrite <- M2 in H0.
rewrite <- Nat.Odd_div2 in H0. rewrite <- Nat.Even_div2 in H0.
apply Nat.Even_succ in H0. rewrite Nat.Even_succ_succ in H0.
apply Nat.Even_EvenT in H0. apply Nat.EvenT_even in H0.
rewrite H0 in H2. inversion H2.
apply Nat.EvenT_Even. apply Nat.even_EvenT. assumption.
apply Nat.OddT_Odd. apply Nat.odd_OddT. rewrite Nat.odd_succ.
assumption.
destruct (length hd). inversion J. apply Nat.lt_0_succ.
assumption.
Qed.