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_1.ma".
17 include "ground/arith/nat_plus.ma".
18 include "ground/arith/nat_pred_succ.ma".
19 include "ground/lib/subset.ma".
20 include "ground/generated/insert_eq_1.ma".
22 (* CLOSED CONDITION FOR PATH ************************************************)
24 inductive pcc: relation2 nat path โ
27 | pcc_d_dx (p) (n) (k):
28 pcc (n+ninj k) p โ pcc n (pโ๐ฑk)
30 pcc n p โ pcc n (pโ๐บ)
32 pcc n p โ pcc (โn) (pโ๐)
34 pcc n p โ pcc n (pโ๐)
36 pcc n p โ pcc n (pโ๐ฆ)
40 "closed condition (path)"
43 (* Basic inversions ********************************************************)
45 lemma pcc_inv_empty (n):
46 (๐) ฯต ๐โจnโฉ โ ๐ = n.
47 #n @(insert_eq_1 โฆ (๐))
49 #p #n [ #k ] #_ #H0 destruct
52 lemma pcc_inv_d_dx (p) (n) (k):
53 pโ๐ฑk ฯต ๐โจnโฉ โ p ฯต ๐โจn+kโฉ.
54 #p #n #h @(insert_eq_1 โฆ (pโ๐ฑh))
56 [|*: #x #n [ #k ] #Hx ] #H0 destruct //
59 lemma pcc_inv_m_dx (p) (n):
60 pโ๐บ ฯต ๐โจnโฉ โ p ฯต ๐โจnโฉ.
61 #p #n @(insert_eq_1 โฆ (pโ๐บ))
63 [|*: #x #n [ #k ] #Hx ] #H0 destruct //
66 lemma pcc_inv_L_dx (p) (n):
67 pโ๐ ฯต ๐โจnโฉ โ
68 โงโง p ฯต ๐โจโnโฉ & โโn = n.
69 #p #n @(insert_eq_1 โฆ (pโ๐))
71 [|*: #x #n [ #k ] #Hx ] #H0 destruct
72 <npred_succ /2 width=1 by conj/
75 lemma pcc_inv_A_dx (p) (n):
76 pโ๐ ฯต ๐โจnโฉ โ p ฯต ๐โจnโฉ.
77 #p #n @(insert_eq_1 โฆ (pโ๐))
79 [|*: #x #n [ #k ] #Hx ] #H0 destruct //
82 lemma pcc_inv_S_dx (p) (n):
83 pโ๐ฆ ฯต ๐โจnโฉ โ p ฯต ๐โจnโฉ.
84 #p #n @(insert_eq_1 โฆ (pโ๐ฆ))
86 [|*: #x #n [ #k ] #Hx ] #H0 destruct //
89 (* Advanced inversions ******************************************************)
91 lemma pcc_inv_empty_succ (n):
92 (๐) ฯต ๐โจโnโฉ โ โฅ.
94 lapply (pcc_inv_empty โฆ H0) -H0 #H0
95 /2 width=7 by eq_inv_zero_nsucc/
98 lemma pcc_inv_L_dx_zero (p):
99 pโ๐ ฯต ๐โจ๐โฉ โ โฅ.
101 elim (pcc_inv_L_dx โฆ H0) -H0 #_ #H0
102 /2 width=7 by eq_inv_nsucc_zero/
105 lemma pcc_inv_L_dx_succ (p) (n):
106 pโ๐ ฯต ๐โจโnโฉ โ p ฯต ๐โจnโฉ.
108 elim (pcc_inv_L_dx โฆ H0) -H0 //
111 (* Main constructions with path_append **************************************)
113 theorem pcc_append_bi (p) (q) (m) (n):
114 p ฯต ๐โจmโฉ โ q ฯต ๐โจnโฉ โ pโq ฯต ๐โจm+nโฉ.
115 #p #q #m #n #Hm #Hm elim Hm -Hm // -Hm
116 #p #n [ #k ] #_ #IH [3: <nplus_succ_dx ]
117 /2 width=1 by pcc_d_dx, pcc_m_dx, pcc_L_dx, pcc_A_dx, pcc_S_dx/
120 (* Main inversions **********************************************************)
122 theorem ppc_mono (q) (n1):
123 q ฯต ๐โจn1โฉ โ โn2. q ฯต ๐โจn2โฉ โ n1 = n2.
124 #q1 #n1 #Hn1 elim Hn1 -q1 -n1
125 [|*: #q1 #n1 [ #k1 ] #_ #IH ] #n2 #Hn2
126 [ <(pcc_inv_empty โฆ Hn2) -n2 //
127 | lapply (pcc_inv_d_dx โฆ Hn2) -Hn2 #Hn2
128 lapply (IH โฆ Hn2) -q1 #H0
129 /2 width=2 by eq_inv_nplus_bi_dx/
130 | lapply (pcc_inv_m_dx โฆ Hn2) -Hn2 #Hn2
131 <(IH โฆ Hn2) -q1 -n2 //
132 | elim (pcc_inv_L_dx โฆ Hn2) -Hn2 #Hn2 #H0
134 | lapply (pcc_inv_A_dx โฆ Hn2) -Hn2 #Hn2
135 <(IH โฆ Hn2) -q1 -n2 //
136 | lapply (pcc_inv_S_dx โฆ Hn2) -Hn2 #Hn2
137 <(IH โฆ Hn2) -q1 -n2 //
141 theorem pcc_inj_L_sn (p1) (p2) (q1) (n):
142 q1 ฯต ๐โจnโฉ โ โq2. q2 ฯต ๐โจnโฉ โ
143 p1โ๐โq1 = p2โ๐โq2 โ q1 = q2.
144 #p1 #p2 #q1 #n #Hq1 elim Hq1 -q1 -n
145 [|*: #q1 #n1 [ #k1 ] #_ #IH ] * //
146 [1,3,5,7,9,11: #l2 #q2 ] #Hq2
147 <list_append_lcons_sn <list_append_lcons_sn #H0
148 elim (eq_inv_list_lcons_bi ????? H0) -H0 #H0 #H1 destruct
149 [ elim (pcc_inv_L_dx_zero โฆ Hq2)
150 | lapply (pcc_inv_d_dx โฆ Hq2) -Hq2 #Hq2
152 | lapply (pcc_inv_m_dx โฆ Hq2) -Hq2 #Hq2
154 | lapply (pcc_inv_L_dx_succ โฆ Hq2) -Hq2 #Hq2
156 | lapply (pcc_inv_A_dx โฆ Hq2) -Hq2 #Hq2
158 | lapply (pcc_inv_S_dx โฆ Hq2) -Hq2 #Hq2
160 | elim (pcc_inv_empty_succ โฆ Hq2)