inductive minuss: nat → relation mr2 ≝
| minuss_nil: ∀i. minuss i (◊) (◊)
| minuss_lt : ∀cs1,cs2,l,m,i. i < l → minuss i cs1 cs2 →
- minuss i ({l, m} @ cs1) ({l - i, m} @ cs2)
+ minuss i (❨l, m❩;cs1) (❨l - i, m❩;cs2)
| minuss_ge : ∀cs1,cs2,l,m,i. l ≤ i → minuss (m + i) cs1 cs2 →
- minuss i ({l, m} @ cs1) cs2
+ minuss i (❨l, m❩;cs1) cs2
.
interpretation "minus (multiple relocation with pairs)"
(* Basic inversion lemmas ***************************************************)
-fact minuss_inv_nil1_aux: â\88\80cs1,cs2,i. cs1 â\96 i â\89¡ cs2 → cs1 = ◊ → cs2 = ◊.
+fact minuss_inv_nil1_aux: â\88\80cs1,cs2,i. cs1 â\96 i â\89\98 cs2 → cs1 = ◊ → cs2 = ◊.
#cs1 #cs2 #i * -cs1 -cs2 -i
[ //
| #cs1 #cs2 #l #m #i #_ #_ #H destruct
]
qed-.
-lemma minuss_inv_nil1: â\88\80cs2,i. â\97\8a â\96 i â\89¡ cs2 → cs2 = ◊.
+lemma minuss_inv_nil1: â\88\80cs2,i. â\97\8a â\96 i â\89\98 cs2 → cs2 = ◊.
/2 width=4 by minuss_inv_nil1_aux/ qed-.
-fact minuss_inv_cons1_aux: â\88\80cs1,cs2,i. cs1 â\96 i â\89¡ cs2 →
- ∀l,m,cs. cs1 = {l, m} @ cs →
- l â\89¤ i â\88§ cs â\96 m + i â\89¡ cs2 ∨
- â\88\83â\88\83cs0. i < l & cs â\96 i â\89¡ cs0 &
- cs2 = {l - i, m} @ cs0.
+fact minuss_inv_cons1_aux: â\88\80cs1,cs2,i. cs1 â\96 i â\89\98 cs2 →
+ ∀l,m,cs. cs1 = ❨l, m❩;cs →
+ l â\89¤ i â\88§ cs â\96 m + i â\89\98 cs2 ∨
+ â\88\83â\88\83cs0. i < l & cs â\96 i â\89\98 cs0 &
+ cs2 = ❨l - i, m❩;cs0.
#cs1 #cs2 #i * -cs1 -cs2 -i
[ #i #l #m #cs #H destruct
| #cs1 #cs #l1 #m1 #i1 #Hil1 #Hcs #l2 #m2 #cs2 #H destruct /3 width=3 by ex3_intro, or_intror/
]
qed-.
-lemma minuss_inv_cons1: ∀cs1,cs2,l,m,i. {l, m} @ cs1 ▭ i ≡ cs2 →
- l â\89¤ i â\88§ cs1 â\96 m + i â\89¡ cs2 ∨
- â\88\83â\88\83cs. i < l & cs1 â\96 i â\89¡ cs &
- cs2 = {l - i, m} @ cs.
+lemma minuss_inv_cons1: ∀cs1,cs2,l,m,i. ❨l, m❩;cs1 ▭ i ≘ cs2 →
+ l â\89¤ i â\88§ cs1 â\96 m + i â\89\98 cs2 ∨
+ â\88\83â\88\83cs. i < l & cs1 â\96 i â\89\98 cs &
+ cs2 = ❨l - i, m❩;cs.
/2 width=3 by minuss_inv_cons1_aux/ qed-.
-lemma minuss_inv_cons1_ge: ∀cs1,cs2,l,m,i. {l, m} @ cs1 ▭ i ≡ cs2 →
- l â\89¤ i â\86\92 cs1 â\96 m + i â\89¡ cs2.
+lemma minuss_inv_cons1_ge: ∀cs1,cs2,l,m,i. ❨l, m❩;cs1 ▭ i ≘ cs2 →
+ l â\89¤ i â\86\92 cs1 â\96 m + i â\89\98 cs2.
#cs1 #cs2 #l #m #i #H
elim (minuss_inv_cons1 … H) -H * // #cs #Hil #_ #_ #Hli
elim (lt_le_false … Hil Hli)
qed-.
-lemma minuss_inv_cons1_lt: ∀cs1,cs2,l,m,i. {l, m} @ cs1 ▭ i ≡ cs2 →
+lemma minuss_inv_cons1_lt: ∀cs1,cs2,l,m,i. ❨l, m❩;cs1 ▭ i ≘ cs2 →
i < l →
- â\88\83â\88\83cs. cs1 â\96 i â\89¡ cs & cs2 = {l - i, m} @ cs.
+ â\88\83â\88\83cs. cs1 â\96 i â\89\98 cs & cs2 = â\9d¨l - i, mâ\9d©;cs.
#cs1 #cs2 #l #m #i #H elim (minuss_inv_cons1 … H) -H * /2 width=3 by ex2_intro/
#Hli #_ #Hil elim (lt_le_false … Hil Hli)
qed-.