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4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
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15 include "nat_ordered_set.ma".
16 include "models/q_support.ma".
17 include "models/list_support.ma".
18 include "cprop_connectives.ma".
20 definition bar ≝ ℚ × ℚ.
22 notation < "\rationals \sup 2" non associative with precedence 90 for @{'q2}.
23 interpretation "Q x Q" 'q2 = (Prod Q Q).
25 definition empty_bar : bar ≝ 〈Qpos one,OQ〉.
26 notation "\rect" with precedence 90 for @{'empty_bar}.
27 interpretation "q0" 'empty_bar = empty_bar.
29 notation < "\ldots\rect\square\EmptySmallSquare\ldots" with precedence 90 for @{'lq2}.
30 interpretation "lq2" 'lq2 = (list bar).
32 inductive sorted : list bar → Prop ≝
33 | sorted_nil : sorted []
34 | sorted_one : ∀x. sorted [x]
35 | sorted_cons : ∀x,y,tl. \fst x < \fst y → sorted (y::tl) → sorted (x::y::tl).
37 definition nth_base ≝ λf,n. \fst (nth f ▭ n).
38 definition nth_height ≝ λf,n. \snd (nth f ▭ n).
42 increasing_bars : sorted bars;
43 bars_begin_OQ : nth_base bars O = OQ;
44 bars_tail_OQ : nth_height bars (pred (len bars)) = OQ
47 lemma nth_nil: ∀T,i.∀def:T. nth [] def i = def.
48 intros; elim i; simplify; [reflexivity;] assumption; qed.
50 lemma all_bases_positives : ∀f:q_f.∀i.i < len (bars f) → OQ < nth_base (bars f) i.
51 intro f; elim (increasing_bars f);
52 [1: unfold nth_base; rewrite > nth_nil; apply (q_pos_OQ one);
53 |2: cases i in H; [2: cases (?:False);
57 λP.λp:∃x:ℚ.P x.match p with [ex_introT p _ ⇒ p].
59 definition inject_Q ≝ λP.λp:ℚ.λh:P p. ex_introT ? P p h.
60 coercion inject_Q with 0 1 nocomposites.
62 definition value_spec : q_f → ℚ → ℚ → Prop ≝
64 ∃j. q = nth_height (bars f) j ∧
65 (nth_base (bars f) j < i ∧
66 ∀n.j < n → n < len (bars f) → i ≤ nth_base (bars f) n).
68 definition value : ∀f:q_f.∀i:ratio.∃p:ℚ.value_spec f (Qpos i) p.
70 alias symbol "lt" (instance 5) = "Q less than".
71 alias symbol "leq" = "Q less or equal than".
72 letin value_spec_aux ≝ (
73 λf,i,q.∃j. q = nth_height f j ∧
74 (nth_base f j < i ∧ ∀n.j < n → n < len f → i ≤ nth_base f n));
76 let rec value (acc: ℚ) (l : list bar) on l : ℚ ≝
80 match q_cmp (\fst x) (Qpos i) with
81 [ q_leq _ ⇒ value (\snd x) tl
84 ∀acc,l.∃p:ℚ. OQ ≤ acc → value_spec_aux l (Qpos i) p);
85 [4: clearbody value; cases (value OQ (bars f)) (p Hp); exists[apply p];
86 cases (Hp (q_le_n ?)) (j Hj); cases Hj (Hjp H); cases H (Hin Hmax);
87 clear Hp value value_spec_aux Hj H; exists [apply j]; split[2:split;intros;]
88 try apply Hmax; assumption;
89 |1: intro Hacc; clear H2; cases (value (\snd b) l1) (j Hj);
90 cases (q_cmp (\snd b) (Qpos i)) (Hib Hib);
91 [1: cases (Hj Hib) (w Hw); simplify in ⊢ (? ? ? %); clear Hib Hj;
92 exists [apply (S w)] cases Hw; cases H3; clear Hw H3;
93 split; try assumption; split; try assumption; intros;
94 apply (q_le_trans ??? (H5 (pred n) ??)); [3: apply q_le_n]
100 cases (q_cmp i (start f));
101 [2: exists [apply 〈O,OQ〉] simplify; constructor 1; split; try assumption;
102 try reflexivity; apply q_lt_to_le; assumption;
103 |1: cases (bars f); [exists [apply 〈O,OQ〉] simplify; constructor 3; split;try assumption;reflexivity;]
104 cases (value ⅆ[i,start f] (b::l)) (p Hp);
105 cases (Hp (q_dist_ge_OQ ? ?)); clear Hp value; [cases H1; destruct H2]
106 cases H1; clear H1; lapply (sum_bases_O (b::l) (\fst p)) as H1;
107 [2: apply (q_le_trans ??? H2); rewrite > H; apply q_eq_to_le;
108 rewrite > q_d_x_x; reflexivity;
109 |1: exists [apply p] simplify; constructor 4; rewrite > H1; split;
110 try split; try rewrite > q_d_x_x; try autobatch depth=2;
111 [1: rewrite > H; rewrite > q_plus_sym; apply q_lt_plus;
112 rewrite > q_plus_minus; apply q_lt_plus_trans; [apply sum_bases_ge_OQ]
114 |2: rewrite > H; rewrite > q_d_x_x; apply q_eq_to_le; reflexivity;
115 |3: rewrite > H; rewrite > q_d_x_x; apply q_lt_plus_trans;
116 try apply sum_bases_ge_OQ; apply q_pos_lt_OQ;]]
117 |3: cases (q_cmp i (start f+sum_bases (bars f) (len (bars f))));
118 [1: exists [apply 〈O,OQ〉] simplify; constructor 2; split; try assumption;
119 try reflexivity; rewrite > H1; apply q_eq_to_le; reflexivity;
120 |3: exists [apply 〈O,OQ〉] simplify; constructor 2; split; try assumption;
121 try reflexivity; apply q_lt_to_le; assumption;
122 |2: generalize in match (refl_eq ? (bars f): bars f = bars f);
123 generalize in match (bars f) in ⊢ (??? % → %); intro X; cases X; clear X;
125 [1: exists [apply 〈O,OQ〉] simplify; constructor 3; split; reflexivity;
126 |2: cases (value ⅆ[i,start f] (b::l)) (p Hp);
127 cases (Hp (q_dist_ge_OQ ? ?)); clear Hp value; [cases H3;destruct H4]
129 exists [apply p]; constructor 4; split; try split; try assumption;
130 [1: intro X; destruct X;
131 |2: apply q_lt_to_le; assumption;
132 |3: rewrite < H2; assumption;
133 |4: cases (cmp_nat (\fst p) (len (bars f)));
134 [1:apply lt_to_le;rewrite <H2; assumption|rewrite > H3;rewrite < H2;apply le_n]
135 cases (?:False); cases (\fst p) in H3 H4 H6; clear H5;
136 [1: intros; apply (not_le_Sn_O ? H5);
137 |2: rewrite > q_d_sym; rewrite > q_d_noabs; [2: apply q_lt_to_le; assumption]
138 intros; lapply (q_lt_inj_plus_r ?? (Qopp (start f)) H1); clear H1;
139 generalize in match Hletin;
140 rewrite > (q_plus_sym (start f)); rewrite < q_plus_assoc;
141 do 2 rewrite < q_elim_minus; rewrite > q_plus_minus;
142 rewrite > q_plus_OQ; intro K; apply (q_lt_corefl (i-start f));
143 apply (q_lt_le_trans ???? H3); rewrite < H2;
144 apply (q_lt_trans ??? K); apply sum_bases_increasing;
146 |1,3: intros; right; split;
147 [1,4: clear H2; cases (value (q-Qpos (\fst b)) l1);
148 cases (H2 (q_le_to_diff_ge_OQ ?? (? H1)));
149 [1: intro; apply q_lt_to_le;assumption;
150 |3: simplify; cases H4; apply q_le_minus; assumption;
151 |2,5: simplify; cases H4; rewrite > H5; rewrite > H6;
152 apply q_le_minus; apply sum_bases_empty_nat_of_q_le_q;
153 |4: intro X; rewrite > X; apply q_eq_to_le; reflexivity;
154 |*: simplify; apply q_le_minus; cases H4; assumption;]
155 |2,5: cases (value (q-Qpos (\fst b)) l1);
156 cases (H4 (q_le_to_diff_ge_OQ ?? (? H1)));
157 [1,4: intros; [apply q_lt_to_le|apply q_eq_to_le;symmetry] assumption;
158 |3,6: cases H5; simplify; change with (q < sum_bases l1 (S (\fst w)) + Qpos (\fst b));
159 apply q_lt_plus; assumption;
160 |2,5: simplify; cases H5; rewrite > H6; simplify; rewrite > H7;
161 apply q_lt_plus; apply sum_bases_empty_nat_of_q_le_q_one;]
162 |*: cases (value (q-Qpos (\fst b)) l1); simplify;
163 cases (H4 (q_le_to_diff_ge_OQ ?? (? H1)));
164 [1,4: intros; [apply q_lt_to_le|apply q_eq_to_le;symmetry] assumption;
165 |3,6: cases H5; assumption;
166 |*: cases H5; rewrite > H6; rewrite > H8;
167 elim (\fst w); [1,3:reflexivity;] simplify; assumption;]]
168 |2: clear value H2; simplify; intros; right; split; [assumption|3:reflexivity]
169 rewrite > q_plus_sym; rewrite > q_plus_OQ; assumption;
170 |4: intros; left; split; reflexivity;]
174 ∀l,i.i < start l → \snd (\fst (value l i)) = OQ.
175 intros; cases (value l i) (q Hq); cases Hq; clear Hq; simplify; cases H1; clear H1;
176 try assumption; cases H2; cases (?:False); apply (q_lt_le_incompat ?? H H6);
180 ∀l,i.start l + sum_bases (bars l) (len (bars l)) ≤ i → \snd (\fst (value l i)) = OQ.
181 intros; cases (value l i) (q Hq); cases Hq; clear Hq; simplify; cases H1; clear H1;
182 try assumption; cases H2; cases (?:False); apply (q_lt_le_incompat ?? H7 H);
186 ∀l,i.bars l = [] → \snd (\fst (value l i)) = OQ.
187 intros; cases (value l i) (q Hq); cases Hq; clear Hq; simplify; cases H1; clear H1;
188 try assumption; cases H2; cases (?:False); apply (H1 H);
191 inductive value_ok_spec (f : q_f) (i : ℚ) : nat × ℚ → Type ≝
192 | value_ok : ∀n,q. n ≤ (len (bars f)) →
193 q = \snd (nth (bars f) ▭ n) →
194 sum_bases (bars f) n ≤ ⅆ[i,start f] →
195 ⅆ[i, start f] < sum_bases (bars f) (S n) → value_ok_spec f i 〈n,q〉.
198 ∀f,i.bars f ≠ [] → start f ≤ i → i < start f + sum_bases (bars f) (len (bars f)) →
199 value_ok_spec f i (\fst (value f i)).
200 intros; cases (value f i); simplify;
201 cases H3; simplify; clear H3; cases H4; clear H4;
202 [1,2,3: cases (?:False);
203 [1: apply (q_lt_le_incompat ?? H3 H1);
204 |2: apply (q_lt_le_incompat ?? H2 H3);
206 |4: cases H7; clear H7; cases w in H3 H4 H5 H6 H8; simplify; intros;
207 constructor 1; assumption;]
210 definition same_values ≝
212 ∀input.\snd (\fst (value l1 input)) = \snd (\fst (value l2 input)).
214 definition same_bases ≝
215 λl1,l2:list bar. (∀i.\fst (nth l1 ▭ i) = \fst (nth l2 ▭ i)).
217 alias symbol "lt" = "Q less than".
218 lemma unpos: ∀x:ℚ.OQ < x → ∃r:ratio.Qpos r = x.
219 intro; cases x; intros; [2:exists [apply r] reflexivity]
221 [ apply (q_lt_corefl ? H)|apply (q_neg_gt ? H)]
224 notation < "x \blacksquare" non associative with precedence 50 for @{'unpos $x}.
225 interpretation "hide unpos proof" 'unpos x = (unpos x _).