1 (**************************************************************************)
4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
10 (* \ / This file is distributed under the terms of the *)
11 (* v GNU General Public License Version 2 *)
13 (**************************************************************************)
15 include "delayed_updating/syntax/path.ma".
16 include "delayed_updating/notation/functions/class_c_3.ma".
17 include "ground/arith/nat_plus_pred.ma".
18 include "ground/lib/subset.ma".
19 include "ground/lib/bool_and.ma".
20 include "ground/generated/insert_eq_1.ma".
21 include "ground/xoa/ex_3_2.ma".
23 (* CLOSED CONDITION FOR PATH ************************************************)
25 inductive pcc (o) (e): relation2 nat path ≝
28 | pcc_d_dx (p) (n) (k):
30 pcc o e (n+ninj k) p → pcc o e n (p◖𝗱k)
32 pcc o e n p → pcc o e n (p◖𝗺)
34 pcc o e n p → pcc o e (↑n) (p◖𝗟)
36 pcc o e n p → pcc o e n (p◖𝗔)
38 pcc o e n p → pcc o e n (p◖𝗦)
42 "closed condition (path)"
43 'ClassC o n e = (pcc o e n).
45 (* Advanced constructions ***************************************************)
47 lemma pcc_false_d_dx (e) (p) (n) (k:pnat):
48 p ϵ 𝐂❨Ⓕ,n+k,e❩ → p◖𝗱k ϵ 𝐂❨Ⓕ,n,e❩.
54 lemma pcc_true_d_dx (e) (p) (n:pnat) (k:pnat):
55 p ϵ 𝐂❨Ⓣ,n+k,e❩ → p◖𝗱k ϵ 𝐂❨Ⓣ,n,e❩.
56 /2 width=1 by pcc_d_dx/
59 lemma pcc_plus_bi_dx (o) (e) (p) (n):
62 #o #e #p #n #H0 elim H0 -p -n //
63 #p #n [ #k #Ho ] #_ #IH #m
64 [|*: /2 width=1 by pcc_m_dx, pcc_L_dx, pcc_A_dx, pcc_S_dx/ ]
66 >Ho -Ho // <nplus_succ_sn //
69 (* Basic inversions ********************************************************)
71 lemma pcc_inv_empty (o) (e) (n):
72 (𝐞) ϵ 𝐂❨o,n,e❩ → e = n.
73 #o #e #n @(insert_eq_1 … (𝐞))
75 #p #n [ #k #_ ] #_ #H0 destruct
79 alias symbol "DownArrow" (instance 4) = "predecessor (non-negative integers)".
80 alias symbol "UpArrow" (instance 3) = "successor (non-negative integers)".
81 alias symbol "and" (instance 1) = "logical and".
83 lemma pcc_inv_d_dx (o) (e) (p) (n) (k):
87 #o #e #p #n #h @(insert_eq_1 … (p◖𝗱h))
89 [|*: #x #n [ #k #Ho ] #Hx ] #H0 destruct
93 lemma pcc_inv_m_dx (o) (e) (p) (n):
94 p◖𝗺 ϵ 𝐂❨o,n,e❩ → p ϵ 𝐂❨o,n,e❩.
95 #o #e #p #n @(insert_eq_1 … (p◖𝗺))
97 [|*: #x #n [ #k #_ ] #Hx ] #H0 destruct //
100 lemma pcc_inv_L_dx (o) (e) (p) (n):
102 ∧∧ p ϵ 𝐂❨o,↓n,e❩ & n = ↑↓n.
103 #o #e #p #n @(insert_eq_1 … (p◖𝗟))
105 [|*: #x #n [ #k #_ ] #Hx ] #H0 destruct
106 <npred_succ /2 width=1 by conj/
109 lemma pcc_inv_A_dx (o) (e) (p) (n):
110 p◖𝗔 ϵ 𝐂❨o,n,e❩ → p ϵ 𝐂❨o,n,e❩.
111 #o #e #p #n @(insert_eq_1 … (p◖𝗔))
113 [|*: #x #n [ #k #_ ] #Hx ] #H0 destruct //
116 lemma pcc_inv_S_dx (o) (e) (p) (n):
117 p◖𝗦 ϵ 𝐂❨o,n,e❩ → p ϵ 𝐂❨o,n,e❩.
118 #o #e #p #n @(insert_eq_1 … (p◖𝗦))
120 [|*: #x #n [ #k #_ ] #Hx ] #H0 destruct //
123 (* Advanced destructions ****************************************************)
125 lemma pcc_des_d_dx (o) (e) (p) (n) (k):
126 p◖𝗱k ϵ 𝐂❨o,n,e❩ → p ϵ 𝐂❨o,n+k,e❩.
128 elim (pcc_inv_d_dx … H0) -H0 #H1 #H2 //
131 lemma pcc_des_gen (o) (e) (p) (n):
132 p ϵ 𝐂❨o,n,e❩ → p ϵ 𝐂❨Ⓕ,n,e❩.
133 #o #e #p #n #H0 elim H0 -p -n //
134 #p #n [ #k #Ho ] #_ #IH
135 /2 width=1 by pcc_m_dx, pcc_L_dx, pcc_A_dx, pcc_S_dx, pcc_false_d_dx/
138 (* Advanced inversions ******************************************************)
140 lemma pcc_inv_empty_succ_zero (o) (n):
143 lapply (pcc_inv_empty … H0) -H0 #H0
144 /2 width=7 by eq_inv_zero_nsucc/
147 lemma pcc_true_inv_d_dx_zero_sn (e) (p) (k):
148 p◖𝗱k ϵ 𝐂❨Ⓣ,𝟎, e❩ → ⊥.
150 elim (pcc_inv_d_dx … H0) -H0 #H0 #_
151 elim (eq_inv_zero_nsucc … (H0 ?)) -H0 //
154 lemma pcc_inv_L_dx_zero_sn (o) (e) (p):
157 elim (pcc_inv_L_dx … H0) -H0 #_ #H0
158 /2 width=7 by eq_inv_zero_nsucc/
161 lemma pcc_inv_L_dx_succ (o) (e) (p) (n):
162 p◖𝗟 ϵ 𝐂❨o,↑n,e❩ → p ϵ 𝐂❨o,n,e❩.
164 elim (pcc_inv_L_dx … H0) -H0 //
167 (* Constructions with land **************************************************)
169 lemma pcc_land_dx (o1) (o2) (e) (p) (n):
170 p ϵ 𝐂❨o1,n,e❩ → p ϵ 𝐂❨o1∧o2,n,e❩.
171 #o1 * /2 width=2 by pcc_des_gen/
174 lemma pcc_land_sn (o1) (o2) (e) (p) (n):
175 p ϵ 𝐂❨o2,n,e❩ → p ϵ 𝐂❨o1∧o2,n,e❩.
176 * /2 width=2 by pcc_des_gen/
179 (* Main constructions with path_append **************************************)
181 theorem pcc_append_bi (o1) (o2) (e1) (e2) (p) (q) (m) (n):
182 p ϵ 𝐂❨o1,m,e1❩ → q ϵ 𝐂❨o2,n,e2❩ → p●q ϵ 𝐂❨o1∧o2,m+n,e1+e2❩.
183 #o1 #o2 #e1 #e2 #p #q #m #n #Hm #Hn elim Hn -q -n
184 /3 width=1 by pcc_land_dx, pcc_m_dx, pcc_A_dx, pcc_S_dx, pcc_plus_bi_dx/
185 #q #n [ #k #Ho2 ] #_ #IH
187 elim (andb_inv_true_sn … H0) -H0 #_ #H0 >Ho2 //
188 <nplus_succ_dx <npred_succ //
189 | <nplus_succ_dx /2 width=1 by pcc_L_dx/
193 (* Inversions with path_append **********************************************)
195 lemma pcc_false_zero_dx_inv_append_bi (x) (m) (n):
197 ∃∃p,q. p ϵ 𝐂❨Ⓕ,m,𝟎❩ & q ϵ 𝐂❨Ⓕ,n,𝟎❩ & p●q = x.
199 @(insert_eq_1 … (m+n) … Hx) -Hx #y #Hy
200 generalize in match n; -n
201 generalize in match m; -m
202 elim Hy -x -y [|*: #x #y [ #k #_ ] #Hx #IH ] #m #n #Hy destruct
203 [ elim (eq_inv_nplus_zero … Hy) -Hy #H1 #H2 destruct
204 /2 width=5 by pcc_empty, ex3_2_intro/
205 | elim (IH m (n+k)) -IH // #p #q #Hp #Hq #H0 destruct -Hx
206 /3 width=5 by pcc_false_d_dx, ex3_2_intro/
207 | elim (IH m n) -IH // #p #q #Hp #Hq #H0 destruct -Hx
208 /3 width=5 by pcc_m_dx, ex3_2_intro/
209 | elim (eq_inv_succ_nplus_dx … (sym_eq … Hy)) -Hy * #H1 #H2 (**) (* sym_eq *)
211 /3 width=5 by pcc_empty, pcc_L_dx, ex3_2_intro/
212 | elim (IH m (↓n)) -IH // #p #q #Hp #Hq #H0 destruct -Hx
213 /3 width=5 by pcc_L_dx, ex3_2_intro/
215 | elim (IH m n) -IH // #p #q #Hp #Hq #H0 destruct -Hx
216 /3 width=5 by pcc_A_dx, ex3_2_intro/
217 | elim (IH m n) -IH // #p #q #Hp #Hq #H0 destruct -Hx
218 /3 width=5 by pcc_S_dx, ex3_2_intro/
223 (* Constructions with path_lcons ********************************************)
225 lemma pcc_m_sn (o) (e) (q) (n):
226 q ϵ 𝐂❨o,n,e❩ → (𝗺◗q) ϵ 𝐂❨o,n,e❩.
228 lapply (pcc_append_bi (Ⓣ) … (𝟎) e … (𝐞◖𝗺) … Hq) -Hq
229 /2 width=3 by pcc_m_dx/
232 lemma pcc_L_sn (o) (e) (q) (n):
233 q ϵ 𝐂❨o,n,e❩ → (𝗟◗q) ϵ 𝐂❨o,↑n,e❩.
235 lapply (pcc_append_bi (Ⓣ) … (𝟎) e … (𝐞◖𝗟) … Hq) -Hq
236 /2 width=3 by pcc_L_dx/
239 lemma pcc_A_sn (o) (e) (q) (n):
240 q ϵ 𝐂❨o,n,e❩ → (𝗔◗q) ϵ 𝐂❨o,n,e❩.
242 lapply (pcc_append_bi (Ⓣ) … (𝟎) e … (𝐞◖𝗔) … Hq) -Hq
243 /2 width=3 by pcc_A_dx/
246 lemma pcc_S_sn (o) (e) (q) (n):
247 q ϵ 𝐂❨o,n,e❩ → (𝗦◗q) ϵ 𝐂❨o,n,e❩.
249 lapply (pcc_append_bi (Ⓣ) … (𝟎) e … (𝐞◖𝗦) … Hq) -Hq
250 /2 width=3 by pcc_S_dx/
253 (* Main inversions **********************************************************)
255 theorem pcc_mono (o1) (o2) (e) (q) (n1):
256 q ϵ 𝐂❨o1,n1,e❩ → ∀n2. q ϵ 𝐂❨o2,n2,e❩ → n1 = n2.
257 #o1 #o2 #e #q1 #n1 #Hn1 elim Hn1 -q1 -n1
258 [|*: #q1 #n1 [ #k1 #_ ] #_ #IH ] #n2 #Hn2
259 [ <(pcc_inv_empty … Hn2) -n2 //
260 | lapply (pcc_des_d_dx … Hn2) -Hn2 #Hn2
261 lapply (IH … Hn2) -q1 #H0
262 /2 width=2 by eq_inv_nplus_bi_dx/
263 | lapply (pcc_inv_m_dx … Hn2) -Hn2 #Hn2
264 <(IH … Hn2) -q1 -n2 //
265 | elim (pcc_inv_L_dx … Hn2) -Hn2 #Hn2 #H0
267 | lapply (pcc_inv_A_dx … Hn2) -Hn2 #Hn2
268 <(IH … Hn2) -q1 -n2 //
269 | lapply (pcc_inv_S_dx … Hn2) -Hn2 #Hn2
270 <(IH … Hn2) -q1 -n2 //
274 theorem pcc_zero_dx_inj_L_sn (o1) (o2) (p1) (p2) (q1) (n):
275 q1 ϵ 𝐂❨o1,n,𝟎❩ → ∀q2. q2 ϵ 𝐂❨o2,n,𝟎❩ →
276 p1●𝗟◗q1 = p2●𝗟◗q2 → q1 = q2.
277 #o1 #o2 #p1 #p2 #q1 #n #Hq1 elim Hq1 -q1 -n
278 [|*: #q1 #n1 [ #k1 #_ ] #_ #IH ] * //
279 [1,3,5,7,9,11: #l2 #q2 ] #Hq2
280 <list_append_lcons_sn <list_append_lcons_sn #H0
281 elim (eq_inv_list_lcons_bi ????? H0) -H0 #H0 #H1 destruct
282 [ elim (pcc_inv_L_dx_zero_sn … Hq2)
283 | lapply (pcc_des_d_dx … Hq2) -Hq2 #Hq2
285 | lapply (pcc_inv_m_dx … Hq2) -Hq2 #Hq2
287 | lapply (pcc_inv_L_dx_succ … Hq2) -Hq2 #Hq2
289 | lapply (pcc_inv_A_dx … Hq2) -Hq2 #Hq2
291 | lapply (pcc_inv_S_dx … Hq2) -Hq2 #Hq2
293 | elim (pcc_inv_empty_succ_zero … Hq2)
297 theorem pcc_inv_L_sn (o) (e) (q) (n) (m):
298 (𝗟◗q) ϵ 𝐂❨o,n,e❩ → q ϵ 𝐂❨o,m,e❩ →
300 #o #e #q #n #m #H1q #H2q
301 lapply (pcc_L_sn … H2q) -H2q #H2q
302 <(pcc_mono … H2q … H1q) -q -n