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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 *)
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15 include "lambda/types.ma".
17 (* MATTER CONCERNING STRONG NORMALIZATION TO BE PUT ELSEWHERE *****************)
19 (* from sn.ma *****************************************************************)
21 (* all(P,l) holds when P holds for all members of l *)
22 let rec all (P:T→Prop) l on l ≝ match l with
24 | cons A D ⇒ P A ∧ all P D
27 (* all(?,P,l1,l2) holds when P holds for all paired members of l1 and l2 *)
28 let rec all2 (A:Type[0]) (P:A→A→Prop) l1 l2 on l1 ≝ match l1 with
30 | cons hd1 tl1 ⇒ match l2 with
32 | cons hd2 tl2 ⇒ P hd1 hd2 ∧ all2 A P tl1 tl2
36 (* Appl F l generalizes App applying F to a list of arguments
37 * The head of l is applied first
39 let rec Appl F l on l ≝ match l with
41 | cons A D ⇒ Appl (App F A) D
44 (* FG: do we need this?
45 definition lift0 ≝ λp,k,M . lift M p k. (**) (* remove definition *)
47 theorem lift_appl: ∀p,k,l,F. lift (Appl F l) p k =
48 Appl (lift F p k) (map … (lift0 p k) l).
49 #p #k #l (elim l) -l /2/ #A #D #IHl #F >IHl //
53 (* from rc.ma *****************************************************************)
55 theorem arith1: ∀x,y. (S x) ≰ (S y) → x ≰ y.
56 #x #y #HS @nmk (elim HS) -HS /3/
59 theorem arith2: ∀i,p,k. k ≤ i → i + p - (k + p) = i - k.
60 #i #p #k #H @plus_to_minus
61 >commutative_plus >(commutative_plus k) >associative_plus @eq_f /2/
64 theorem arith3: ∀x,y,z. x ≰ y → x + z ≰ y + z.
65 #x #y #z #H @nmk (elim H) -H /3/
68 theorem length_append: ∀A. ∀(l2,l1:list A). |l1@l2| = |l1| + |l2|.
69 #A #l2 #l1 (elim l1) -l1 (normalize) //
72 theorem lift_rel_lt: ∀i,p,k. (S i) ≤ k → lift (Rel i) k p = Rel i.
73 #i #p #k #Hik normalize >(le_to_leb_true … Hik) //
76 theorem lift_rel_ge: ∀i,p,k. (S i) ≰ k → lift (Rel i) k p = Rel (i+p).
77 #i #p #k #Hik normalize >(lt_to_leb_false (S i) k) /2/
80 theorem lift_app: ∀M,N,k,p.
81 lift (App M N) k p = App (lift M k p) (lift N k p).
84 theorem lift_lambda: ∀N,M,k,p. lift (Lambda N M) k p =
85 Lambda (lift N k p) (lift M (k + 1) p).
88 theorem lift_prod: ∀N,M,k,p.
89 lift (Prod N M) k p = Prod (lift N k p) (lift M (k + 1) p).
92 (* telescopic non-delifting substitution of l in M.
93 * [this is the telescoping delifting substitution lifted by |l|]
94 * Rel 0 is replaced with the head of l
96 let rec substc M l on l ≝ match l with
98 | cons A D ⇒ (lift (substc M[0≝A] D) 0 1)
101 notation "M [ l ]" non associative with precedence 90 for @{'Substc $M $l}.
103 interpretation "Substc" 'Substc M l = (substc M l).
105 (* this is just to test that substitution works as expected
106 theorem test1: ∀A,B,C. (App (App (Rel 0) (Rel 1)) (Rel 2))[A::B::C::nil ?] =
107 App (App (lift A 0 1) (lift B 0 2)) (lift C 0 3).
109 >lift_0 >lift_0 >lift_0
110 >lift_lift1>lift_lift1>lift_lift1>lift_lift1>lift_lift1>lift_lift1
115 theorem substc_refl: ∀l,t. (lift t 0 (|l|))[l] = (lift t 0 (|l|)).
116 #l (elim l) -l (normalize) // #A #D #IHl #t cut (S (|D|) = |D| + 1) // (**) (* eliminate cut *)
119 theorem substc_sort: ∀n,l. (Sort n)[l] = Sort n.
122 (* FG: not needed for now
124 inductive neutral: T → Prop ≝
125 | neutral_sort: ∀n.neutral (Sort n)
126 | neutral_rel: ∀i.neutral (Rel i)
127 | neutral_app: ∀M,N.neutral (App M N)