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4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.tcs.unibo.it *)
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15 include "ground/notation/relations/ratsucc_3.ma".
16 include "ground/arith/nat_lt_pred.ma".
17 include "ground/relocation/rtmap_at.ma".
19 (* NON-NEGATIVE APPLICATION FOR RELOCATION MAPS *****************************)
21 definition rm_nat: relation3 rtmap nat nat ≝
22 λf,l1,l2. @❪↑l1,f❫ ≘ ↑l2.
25 "relational non-negative application (relocation maps)"
26 'RAtSucc l1 f l2 = (rm_nat f l1 l2).
28 (* Basic properties *********************************************************)
30 lemma rm_nat_refl (f) (g) (k1) (k2):
31 (⫯f) = g → 𝟎 = k1 → 𝟎 = k2 → @↑❪k1,g❫ ≘ k2.
32 #f #g #k1 #k2 #H1 #H2 #H3 destruct
33 /2 width=2 by at_refl/
36 lemma rm_nat_push (f) (l1) (l2) (g) (k1) (k2):
37 @↑❪l1,f❫ ≘ l2 → ⫯f = g → ↑l1 = k1 → ↑l2 = k2 → @↑❪k1,g❫ ≘ k2.
38 #f #l1 #l2 #g #k1 #k2 #Hf #H1 #H2 #H3 destruct
39 /2 width=7 by at_push/
42 lemma rm_nat_next (f) (l1) (l2) (g) (k2):
43 @↑❪l1,f❫ ≘ l2 → ↑f = g → ↑l2 = k2 → @↑❪l1,g❫ ≘ k2.
44 #f #l1 #l2 #g #k2 #Hf #H1 #H2 destruct
45 /2 width=5 by at_next/
48 lemma rm_nat_pred_bi (f) (i1) (i2):
49 @❪i1,f❫ ≘ i2 → @↑❪↓i1,f❫ ≘ ↓i2.
51 >(npsucc_pred i1) in ⊢ (%→?); >(npsucc_pred i2) in ⊢ (%→?);
55 (* Basic inversion lemmas ***************************************************)
57 lemma rm_nat_inv_ppx (f) (l1) (l2):
58 @↑❪l1,f❫ ≘ l2 → ∀g. 𝟎 = l1 → ⫯g = f → 𝟎 = l2.
59 #f #l1 #l2 #H #g #H1 #H2 destruct
60 lapply (at_inv_ppx … H ???) -H
61 /2 width=2 by eq_inv_npsucc_bi/
64 lemma rm_nat_inv_npx (f) (l1) (l2):
65 @↑❪l1,f❫ ≘ l2 → ∀g,k1. ↑k1 = l1 → ⫯g = f →
66 ∃∃k2. @↑❪k1,g❫ ≘ k2 & ↑k2 = l2.
67 #f #l1 #l2 #H #g #k1 #H1 #H2 destruct
68 elim (at_inv_npx … H) -H [|*: // ] #k2 #Hg
69 >(npsucc_pred (↑l2)) #H
70 @(ex2_intro … (↓k2)) //
74 lemma rm_nat_inv_xnx (f) (l1) (l2):
75 @↑❪l1,f❫ ≘ l2 → ∀g. ↑g = f →
76 ∃∃k2. @↑❪l1,g❫ ≘ k2 & ↑k2 = l2.
77 #f #l1 #l2 #H #g #H1 destruct
78 elim (at_inv_xnx … H) -H [|*: // ] #k2
79 >(npsucc_pred (k2)) in ⊢ (%→?→?); #Hg #H
80 @(ex2_intro … (↓k2)) //
84 (* Advanced inversion lemmas ************************************************)
86 lemma rm_nat_inv_ppn (f) (l1) (l2):
87 @↑❪l1,f❫ ≘ l2 → ∀g,k2. 𝟎 = l1 → ⫯g = f → ↑k2 = l2 → ⊥.
88 #f #l1 #l2 #Hf #g #k2 #H1 #H <(rm_nat_inv_ppx … Hf … H1 H) -f -g -l1 -l2
89 /2 width=3 by eq_inv_nsucc_zero/
92 lemma rm_nat_inv_npp (f) (l1) (l2):
93 @↑❪l1,f❫ ≘ l2 → ∀g,k1. ↑k1 = l1 → ⫯g = f → 𝟎 = l2 → ⊥.
94 #f #l1 #l2 #Hf #g #k1 #H1 #H elim (rm_nat_inv_npx … Hf … H1 H) -f -l1
95 #x2 #Hg * -l2 /2 width=3 by eq_inv_zero_nsucc/
98 lemma rm_nat_inv_npn (f) (l1) (l2):
99 @↑❪l1,f❫ ≘ l2 → ∀g,k1,k2. ↑k1 = l1 → ⫯g = f → ↑k2 = l2 → @↑❪k1,g❫ ≘ k2.
100 #f #l1 #l2 #Hf #g #k1 #k2 #H1 #H elim (rm_nat_inv_npx … Hf … H1 H) -f -l1
101 #x2 #Hg * -l2 #H >(eq_inv_nsucc_bi … H) -k2 //
104 lemma rm_nat_inv_xnp (f) (l1) (l2):
105 @↑❪l1,f❫ ≘ l2 → ∀g. ↑g = f → 𝟎 = l2 → ⊥.
106 #f #l1 #l2 #Hf #g #H elim (rm_nat_inv_xnx … Hf … H) -f
107 #x2 #Hg * -l2 /2 width=3 by eq_inv_zero_nsucc/
110 lemma rm_nat_inv_xnn (f) (l1) (l2):
111 @↑❪l1,f❫ ≘ l2 → ∀g,k2. ↑g = f → ↑k2 = l2 → @↑❪l1,g❫ ≘ k2.
112 #f #l1 #l2 #Hf #g #k2 #H elim (rm_nat_inv_xnx … Hf … H) -f
113 #x2 #Hg * -l2 #H >(eq_inv_nsucc_bi … H) -k2 //
116 lemma rm_nat_inv_pxp (f) (l1) (l2):
117 @↑❪l1,f❫ ≘ l2 → 𝟎 = l1 → 𝟎 = l2 → ∃g. ⫯g = f.
118 #f elim (pn_split … f) * /2 width=2 by ex_intro/
119 #g #H #l1 #l2 #Hf #H1 #H2 cases (rm_nat_inv_xnp … Hf … H H2)
122 lemma rm_nat_inv_pxn (f) (l1) (l2):
123 @↑❪l1,f❫ ≘ l2 → ∀k2. 𝟎 = l1 → ↑k2 = l2 →
124 ∃∃g. @↑❪l1,g❫ ≘ k2 & ↑g = f.
125 #f elim (pn_split … f) *
126 #g #H #l1 #l2 #Hf #k2 #H1 #H2
127 [ elim (rm_nat_inv_ppn … Hf … H1 H H2)
128 | /3 width=5 by rm_nat_inv_xnn, ex2_intro/
132 lemma rm_nat_inv_nxp (f) (l1) (l2):
133 @↑❪l1,f❫ ≘ l2 → ∀k1. ↑k1 = l1 → 𝟎 = l2 → ⊥.
134 #f elim (pn_split f) *
135 #g #H #l1 #l2 #Hf #k1 #H1 #H2
136 [ elim (rm_nat_inv_npp … Hf … H1 H H2)
137 | elim (rm_nat_inv_xnp … Hf … H H2)
141 lemma rm_nat_inv_nxn (f) (l1) (l2):
142 @↑❪l1,f❫ ≘ l2 → ∀k1,k2. ↑k1 = l1 → ↑k2 = l2 →
143 ∨∨ ∃∃g. @↑❪k1,g❫ ≘ k2 & ⫯g = f
144 | ∃∃g. @↑❪l1,g❫ ≘ k2 & ↑g = f.
145 #f elim (pn_split f) *
146 /4 width=7 by rm_nat_inv_xnn, rm_nat_inv_npn, ex2_intro, or_intror, or_introl/
149 (* Note: the following inversion lemmas must be checked *)
150 lemma rm_nat_inv_xpx (f) (l1) (l2):
151 @↑❪l1,f❫ ≘ l2 → ∀g. ⫯g = f →
152 ∨∨ ∧∧ 𝟎 = l1 & 𝟎 = l2
153 | ∃∃k1,k2. @↑❪k1,g❫ ≘ k2 & ↑k1 = l1 & ↑k2 = l2.
154 #f * [2: #l1 ] #l2 #Hf #g #H
155 [ elim (rm_nat_inv_npx … Hf … H) -f /3 width=5 by or_intror, ex3_2_intro/
156 | >(rm_nat_inv_ppx … Hf … H) -f /3 width=1 by conj, or_introl/
160 lemma rm_nat_inv_xpp (f) (l1) (l2):
161 @↑❪l1,f❫ ≘ l2 → ∀g. ⫯g = f → 𝟎 = l2 → 𝟎 = l1.
162 #f #l1 #l2 #Hf #g #H elim (rm_nat_inv_xpx … Hf … H) -f * //
163 #k1 #k2 #_ #_ * -l2 #H elim (eq_inv_zero_nsucc … H)
166 lemma rm_nat_inv_xpn (f) (l1) (l2):
167 @↑❪l1,f❫ ≘ l2 → ∀g,k2. ⫯g = f → ↑k2 = l2 →
168 ∃∃k1. @↑❪k1,g❫ ≘ k2 & ↑k1 = l1.
169 #f #l1 #l2 #Hf #g #k2 #H elim (rm_nat_inv_xpx … Hf … H) -f *
170 [ #_ * -l2 #H elim (eq_inv_nsucc_zero … H)
171 | #x1 #x2 #Hg #H1 * -l2 #H
172 lapply (eq_inv_nsucc_bi … H) -H #H destruct
173 /2 width=3 by ex2_intro/
177 lemma rm_nat_inv_xxp (f) (l1) (l2):
178 @↑❪l1,f❫ ≘ l2 → 𝟎 = l2 → ∃∃g. 𝟎 = l1 & ⫯g = f.
179 #f elim (pn_split f) *
180 #g #H #l1 #l2 #Hf #H2
181 [ /3 width=6 by rm_nat_inv_xpp, ex2_intro/
182 | elim (rm_nat_inv_xnp … Hf … H H2)
186 lemma rm_nat_inv_xxn (f) (l1) (l2): @↑❪l1,f❫ ≘ l2 → ∀k2. ↑k2 = l2 →
187 ∨∨ ∃∃g,k1. @↑❪k1,g❫ ≘ k2 & ↑k1 = l1 & ⫯g = f
188 | ∃∃g. @↑❪l1,g❫ ≘ k2 & ↑g = f.
189 #f elim (pn_split f) *
190 #g #H #l1 #l2 #Hf #k2 #H2
191 [ elim (rm_nat_inv_xpn … Hf … H H2) -l2 /3 width=5 by or_introl, ex3_2_intro/
192 | lapply (rm_nat_inv_xnn … Hf … H H2) -l2 /3 width=3 by or_intror, ex2_intro/
196 (* Main destructions ********************************************************)
198 theorem rm_nat_monotonic (k2) (l2) (f):
199 @↑❪l2,f❫ ≘ k2 → ∀k1,l1. @↑❪l1,f❫ ≘ k1 → l1 < l2 → k1 < k2.
200 #k2 @(nat_ind_succ … k2) -k2
201 [ #l2 #f #H2f elim (rm_nat_inv_xxp … H2f) -H2f //
202 #g #H21 #_ #k1 #l1 #_ #Hi destruct
203 elim (nlt_inv_zero_dx … Hi)
204 | #k2 #IH #l2 #f #H2f #k1 @(nat_ind_succ … k1) -k1 //
205 #k1 #_ #l1 #H1f #Hl elim (nlt_inv_gen … Hl)
206 #_ #Hl2 elim (rm_nat_inv_nxn … H2f (↓l2)) -H2f [1,3: * |*: // ]
208 [ elim (rm_nat_inv_xpn … H1f … H) -f
209 /4 width=8 by nlt_inv_succ_bi, nlt_succ_bi/
210 | /4 width=8 by rm_nat_inv_xnn, nlt_succ_bi/
215 theorem rm_nat_inv_monotonic (k1) (l1) (f):
216 @↑❪l1,f❫ ≘ k1 → ∀k2,l2. @↑❪l2,f❫ ≘ k2 → k1 < k2 → l1 < l2.
217 #k1 @(nat_ind_succ … k1) -k1
218 [ #l1 #f #H1f elim (rm_nat_inv_xxp … H1f) -H1f //
219 #g * -l1 #H #k2 #l2 #H2f #Hk
220 lapply (nlt_des_gen … Hk) -Hk #H22
221 elim (rm_nat_inv_xpn … H2f … (↓k2) H) -f //
222 | #k1 #IH #l1 @(nat_ind_succ … l1) -l1
223 [ #f #H1f elim (rm_nat_inv_pxn … H1f) -H1f [ |*: // ]
224 #g #H1g #H #k2 #l2 #H2f #Hj elim (nlt_inv_succ_sn … Hj) -Hj
225 /3 width=7 by rm_nat_inv_xnn/
226 | #l1 #_ #f #H1f #k2 #l2 #H2f #Hj elim (nlt_inv_succ_sn … Hj) -Hj
227 #Hj #H22 elim (rm_nat_inv_nxn … H1f) -H1f [1,4: * |*: // ]
229 [ elim (rm_nat_inv_xpn … H2f … (↓k2) H) -f
230 /3 width=7 by nlt_succ_bi/
231 | /3 width=7 by rm_nat_inv_xnn/
237 theorem rm_nat_mono (f) (l) (l1) (l2):
238 @↑❪l,f❫ ≘ l1 → @↑❪l,f❫ ≘ l2 → l2 = l1.
239 #f #l #l1 #l2 #H1 #H2 elim (nat_split_lt_eq_gt l2 l1) //
240 #Hi elim (nlt_ge_false l l) /3 width=6 by rm_nat_inv_monotonic, eq_sym/
243 theorem rm_nat_inj (f) (l1) (l2) (l):
244 @↑❪l1,f❫ ≘ l → @↑❪l2,f❫ ≘ l → l1 = l2.
245 #f #l1 #l2 #l #H1 #H2 elim (nat_split_lt_eq_gt l2 l1) //
246 #Hi elim (nlt_ge_false l l) /2 width=6 by rm_nat_monotonic/