(* This file is generated by Why3's Coq driver *)
(* Beware! Only edit allowed sections below    *)
Require Import BuiltIn.
Require BuiltIn.
Require HighOrd.
Require int.Int.
Require map.Map.

(* Why3 assumption *)
Inductive ref (a:Type) :=
  | ref'mk : a -> ref a.
Axiom ref_WhyType : forall (a:Type) {a_WT:WhyType a}, WhyType (ref a).
Existing Instance ref_WhyType.
Arguments ref'mk {a}.

(* Why3 assumption *)
Definition contents {a:Type} {a_WT:WhyType a} (v:ref a) : a :=
  match v with
  | ref'mk x => x
  end.

Axiom array : forall (a:Type), Type.
Parameter array_WhyType :
  forall (a:Type) {a_WT:WhyType a}, WhyType (array a).
Existing Instance array_WhyType.

Parameter elts:
  forall {a:Type} {a_WT:WhyType a}, array a -> Numbers.BinNums.Z -> a.

Parameter length:
  forall {a:Type} {a_WT:WhyType a}, array a -> Numbers.BinNums.Z.

Axiom array'invariant :
  forall {a:Type} {a_WT:WhyType a},
  forall (self:array a), (0%Z <= (length self))%Z.

(* Why3 assumption *)
Definition mixfix_lbrb {a:Type} {a_WT:WhyType a} (a1:array a)
    (i:Numbers.BinNums.Z) : a :=
  elts a1 i.

Parameter mixfix_lblsmnrb:
  forall {a:Type} {a_WT:WhyType a}, array a -> Numbers.BinNums.Z -> a ->
  array a.

Axiom mixfix_lblsmnrb'spec'0 :
  forall {a:Type} {a_WT:WhyType a},
  forall (a1:array a) (i:Numbers.BinNums.Z) (v:a),
  ((length (mixfix_lblsmnrb a1 i v)) = (length a1)).

Axiom mixfix_lblsmnrb'spec :
  forall {a:Type} {a_WT:WhyType a},
  forall (a1:array a) (i:Numbers.BinNums.Z) (v:a),
  ((elts (mixfix_lblsmnrb a1 i v)) = (map.Map.set (elts a1) i v)).

Parameter make:
  forall {a:Type} {a_WT:WhyType a}, Numbers.BinNums.Z -> a -> array a.

Axiom make_spec :
  forall {a:Type} {a_WT:WhyType a},
  forall (n:Numbers.BinNums.Z) (v:a), (0%Z <= n)%Z ->
  (forall (i:Numbers.BinNums.Z), (0%Z <= i)%Z /\ (i < n)%Z ->
   ((mixfix_lbrb (make n v) i) = v)) /\
  ((length (make n v)) = n).

Axiom char : Type.
Parameter char_WhyType : WhyType char.
Existing Instance char_WhyType.

(* Why3 assumption *)
Definition matches (a1:array char) (i1:Numbers.BinNums.Z) (a2:array char)
    (i2:Numbers.BinNums.Z) (n:Numbers.BinNums.Z) : Prop :=
  ((0%Z <= i1)%Z /\ (i1 <= ((length a1) - n)%Z)%Z) /\
  ((0%Z <= i2)%Z /\ (i2 <= ((length a2) - n)%Z)%Z) /\
  (forall (i:Numbers.BinNums.Z), (0%Z <= i)%Z /\ (i < n)%Z ->
   ((mixfix_lbrb a1 (i1 + i)%Z) = (mixfix_lbrb a2 (i2 + i)%Z))).

Axiom matches_empty :
  forall (a1:array char) (a2:array char) (i1:Numbers.BinNums.Z)
    (i2:Numbers.BinNums.Z),
  (0%Z <= i1)%Z /\ (i1 <= (length a1))%Z ->
  (0%Z <= i2)%Z /\ (i2 <= (length a2))%Z -> matches a1 i1 a2 i2 0%Z.

Axiom matches_right_extension :
  forall (a1:array char) (a2:array char) (i1:Numbers.BinNums.Z)
    (i2:Numbers.BinNums.Z) (n:Numbers.BinNums.Z),
  matches a1 i1 a2 i2 n -> (i1 <= (((length a1) - n)%Z - 1%Z)%Z)%Z ->
  (i2 <= (((length a2) - n)%Z - 1%Z)%Z)%Z ->
  ((mixfix_lbrb a1 (i1 + n)%Z) = (mixfix_lbrb a2 (i2 + n)%Z)) ->
  matches a1 i1 a2 i2 (n + 1%Z)%Z.

Axiom matches_contradiction_at_first :
  forall (a1:array char) (a2:array char) (i1:Numbers.BinNums.Z)
    (i2:Numbers.BinNums.Z) (n:Numbers.BinNums.Z),
  (0%Z < n)%Z -> ~ ((mixfix_lbrb a1 i1) = (mixfix_lbrb a2 i2)) ->
  ~ matches a1 i1 a2 i2 n.

Axiom matches_contradiction_at_i :
  forall (a1:array char) (a2:array char) (i1:Numbers.BinNums.Z)
    (i2:Numbers.BinNums.Z) (i:Numbers.BinNums.Z) (n:Numbers.BinNums.Z),
  (0%Z < n)%Z -> (0%Z <= i)%Z /\ (i < n)%Z ->
  ~ ((mixfix_lbrb a1 (i1 + i)%Z) = (mixfix_lbrb a2 (i2 + i)%Z)) ->
  ~ matches a1 i1 a2 i2 n.

Axiom matches_right_weakening :
  forall (a1:array char) (a2:array char) (i1:Numbers.BinNums.Z)
    (i2:Numbers.BinNums.Z) (n:Numbers.BinNums.Z) (n':Numbers.BinNums.Z),
  matches a1 i1 a2 i2 n -> (n' < n)%Z -> matches a1 i1 a2 i2 n'.

Axiom matches_left_weakening :
  forall (a1:array char) (a2:array char) (i1:Numbers.BinNums.Z)
    (i2:Numbers.BinNums.Z) (n:Numbers.BinNums.Z) (n':Numbers.BinNums.Z),
  matches a1 (i1 - (n - n')%Z)%Z a2 (i2 - (n - n')%Z)%Z n -> (n' < n)%Z ->
  matches a1 i1 a2 i2 n'.

Axiom matches_sym :
  forall (a1:array char) (a2:array char) (i1:Numbers.BinNums.Z)
    (i2:Numbers.BinNums.Z) (n:Numbers.BinNums.Z),
  matches a1 i1 a2 i2 n -> matches a2 i2 a1 i1 n.

Axiom matches_trans :
  forall (a1:array char) (a2:array char) (a3:array char)
    (i1:Numbers.BinNums.Z) (i2:Numbers.BinNums.Z) (i3:Numbers.BinNums.Z)
    (n:Numbers.BinNums.Z),
  matches a1 i1 a2 i2 n -> matches a2 i2 a3 i3 n -> matches a1 i1 a3 i3 n.

(* Why3 assumption *)
Definition is_next (p:array char) (j:Numbers.BinNums.Z)
    (n:Numbers.BinNums.Z) : Prop :=
  ((0%Z <= n)%Z /\ (n < j)%Z) /\
  matches p (j - n)%Z p 0%Z n /\
  (forall (z:Numbers.BinNums.Z), (n < z)%Z /\ (z < j)%Z ->
   ~ matches p (j - z)%Z p 0%Z z).

Axiom next_iteration :
  forall (p:array char) (a:array char) (i:Numbers.BinNums.Z)
    (j:Numbers.BinNums.Z) (n:Numbers.BinNums.Z),
  (0%Z < j)%Z /\ (j < (length p))%Z -> (j <= i)%Z /\ (i <= (length a))%Z ->
  matches a (i - j)%Z p 0%Z j -> is_next p j n -> matches a (i - n)%Z p 0%Z n.

Axiom next_is_maximal :
  forall (p:array char) (a:array char) (i:Numbers.BinNums.Z)
    (j:Numbers.BinNums.Z) (n:Numbers.BinNums.Z) (k:Numbers.BinNums.Z),
  (0%Z < j)%Z /\ (j < (length p))%Z -> (j <= i)%Z /\ (i <= (length a))%Z ->
  ((i - j)%Z < k)%Z /\ (k < (i - n)%Z)%Z -> matches a (i - j)%Z p 0%Z j ->
  is_next p j n -> ~ matches a k p 0%Z (length p).

Axiom next_1_0 :
  forall (p:array char), (1%Z <= (length p))%Z -> is_next p 1%Z 0%Z.

Require Import Lia.

(* Why3 goal *)
Theorem initnext'vc :
  forall (p:array char), (1%Z <= (length p))%Z ->
  let m := length p in
  forall (next:array Numbers.BinNums.Z),
  (forall (i:Numbers.BinNums.Z), (0%Z <= i)%Z /\ (i < m)%Z ->
   ((mixfix_lbrb next i) = 0%Z)) /\
  ((length next) = m) -> (1%Z < m)%Z ->
  forall (next1:array Numbers.BinNums.Z), ((length next1) = (length next)) ->
  ((elts next1) = (map.Map.set (elts next) 1%Z 0%Z)) /\
  (next1 = (mixfix_lblsmnrb next 1%Z 0%Z)) ->
  forall (j:Numbers.BinNums.Z) (i:Numbers.BinNums.Z)
    (next2:array Numbers.BinNums.Z),
  ((length next2) = (length next1)) ->
  ((0%Z <= j)%Z /\ (j < i)%Z /\ (i <= m)%Z) /\
  matches p (i - j)%Z p 0%Z j /\
  (forall (z:Numbers.BinNums.Z),
   ((j + 1%Z)%Z < z)%Z /\ (z < (i + 1%Z)%Z)%Z ->
   ~ matches p ((i + 1%Z)%Z - z)%Z p 0%Z z) /\
  (forall (k:Numbers.BinNums.Z), (0%Z < k)%Z /\ (k <= i)%Z ->
   is_next p k (mixfix_lbrb next2 k)) ->
  (i < (m - 1%Z)%Z)%Z -> ~ ((mixfix_lbrb p i) = (mixfix_lbrb p j)) ->
  (j = 0%Z) -> forall (i1:Numbers.BinNums.Z), (i1 = (i + 1%Z)%Z) ->
  forall (next3:array Numbers.BinNums.Z),
  ((length next3) = (length next2)) ->
  ((elts next3) = (map.Map.set (elts next2) i1 0%Z)) /\
  (next3 = (mixfix_lblsmnrb next2 i1 0%Z)) ->
  (0%Z <= j)%Z /\ (j < i1)%Z /\ (i1 <= m)%Z ->
  matches p (i1 - j)%Z p 0%Z j -> forall (z:Numbers.BinNums.Z),
  ((j + 1%Z)%Z < z)%Z /\ (z < (i1 + 1%Z)%Z)%Z ->
  ~ matches p ((i1 + 1%Z)%Z - z)%Z p 0%Z z.
(* Why3 intros p h1 m next (h2,h3) h4 next1 h5 (h6,h7) j i next2 h8
        ((h9,(h10,h11)),(h12,(h13,h14))) h15 h16 h17 i1 h18 next3 h19
        (h20,h21) (h22,(h23,h24)) h25 z (h26,h27). *)
Proof.
intros p h1 m next (h2,h3) h4 next1 h5 h6 j i next2 h7
((h8,(h9,h10)),(h11,(h12,h13))) h14 h15 h16 i1 h17 next3 h18 h19
(h20,(h21,h22)) h23 z (h24,h25).
(*
intros n p1.
intro p3. unfold p3. clear p3.
intros (_,hn) _ next next1 _ _ _ _ _.
intros j i next4 ((hj,hi),(h0,(h1,h2))).
intros hi' _ _ neq j0. subst j.
intros i1 hi1; subst i1.
intros _ _ _ z hz.
*)
red; intro h. unfold matches in h. simpl in h.
destruct h as (hy1, (hy2, hy3)).

assert (case: (z = 2 \/ 2 < z)%Z) by lia. destruct case.
subst.
absurd (elts p i = elts p 0%Z); auto.
generalize (hy3 0%Z).
ring_simplify (i + 1 + 1 - 2 + 0)%Z.
intuition.

apply h12 with (z-1)%Z.
lia.
red; simpl.
repeat split; try lia.
intros; subst i1.
replace (i + 1 - (z - 1) + i0)%Z with (i + 1 + 1 - z + i0)%Z by lia.
apply hy3.
lia.
Qed.

