internlm/Lean-Github huggingface dataset:
Theorem: partitionImpl.loop_invariant
Proof state before:
case kj.h
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
result : { mid // first ≤ mid ∧ mid ≤ j } × Vec α n
eq : partitionImpl arr first i j fi✝ ij = result
swapped : Vec α n := arr.swap i j
⊢ ¬↑first = ↑j
Tactic:
exact Nat.ne_of_lt (Nat.lt_of_lt_of_le fi ij)
Proof state after:
no goals
Theorem: partitionImpl.loop_invariant
Proof state before:
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
result : { mid // first ≤ mid ∧ mid ≤ j } × Vec α n
eq : partitionImpl arr first i j fi✝ ij = result
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
⊢ first ≤ i.prev
Tactic:
assumption
Proof state after:
no goals
Theorem: partitionImpl.loop_invariant
Proof state before:
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
result : { mid // first ≤ mid ∧ mid ≤ j } × Vec α n
eq : partitionImpl arr first i j fi✝ ij = result
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
⊢ i.prev ≤ j.prev
Tactic:
assumption
Proof state after:
no goals
Theorem: partitionImpl.loop_invariant
Proof state before:
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
⊢ LoopInvariant swapped first i.prev j.prev last
Tactic:
apply LoopInvariant.intro
Proof state after:
case inv₁
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
⊢ ∀ (k : Fin n), i.prev < k → k < j.prev → swapped[k] < swapped[first]

case inv₂
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
⊢ ∀ (k : Fin n), j.prev < k → k ≤ last → ¬swapped[k] < swapped[first]

case inv₃
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
⊢ i.prev < j.prev → swapped[j.prev] < swapped[first]
Theorem: partitionImpl.loop_invariant
Proof state before:
case inv₂
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
⊢ ∀ (k : Fin n), j.prev < k → k ≤ last → ¬swapped[k] < swapped[first]

case inv₃
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
⊢ i.prev < j.prev → swapped[j.prev] < swapped[first]
Tactic:
. intro k jk kl
  have jk : j.val ≤ k.val := by
    rw [←Nat.sub_add_cancel (Nat.zero_lt_of_lt (Nat.zero_lt_of_lt (Nat.lt_of_lt_of_le fi ij)))]
    exact jk
  cases Nat.eq_or_lt_of_le jk with
  | inl jk =>
    have : swapped[k] = arr[i] := by
      simp [Fin.eq_of_val_eq jk.symm]
      apply Vec.get_swap_right
    rw [this, sf]
    assumption
  | inr jk =>
    have : swapped[k] = arr[k] := by
      apply Vec.get_swap_neq
      . apply Fin.ne_of_val_ne
        exact Nat.ne_of_gt (Nat.lt_of_le_of_lt ij jk)
      . apply Fin.ne_of_val_ne
        exact Nat.ne_of_gt jk
    rw [this, sf]
    exact inv.2 k jk kl
Proof state after:
case inv₃
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
⊢ i.prev < j.prev → swapped[j.prev] < swapped[first]
Theorem: partitionImpl.loop_invariant
Proof state before:
case inv₃
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
⊢ i.prev < j.prev → swapped[j.prev] < swapped[first]
Tactic:
. intro ij
  have : j.val - 1 < j.val := by
    show j.val - 1 + 1 ≤ j.val
    rw [Nat.sub_add_cancel (Nat.zero_lt_of_lt (Nat.lt_of_lt_of_le fi (by assumption)))]
    apply Nat.le_refl
  have ij : i.val ≤ j.val - 1 := by
    rw [←Nat.sub_add_cancel (Nat.zero_lt_of_lt fi)]
    exact ij
  cases Nat.eq_or_lt_of_le ij with
  | inl ij =>
    have : swapped[j.prev] = arr[j] := by
      simp [ij.symm, Fin.prev]
      apply Vec.get_swap_left
    rw [this, sf]
    have : i < j := Nat.lt_of_le_of_lt (by assumption : i.val ≤ j.val - 1) (by assumption)
    exact inv.3 this
  | inr ij =>
    have : swapped[j.prev] = arr[j.prev] := by
      apply Vec.get_swap_neq
      . apply Fin.ne_of_val_ne
        exact Nat.ne_of_gt ij
      . apply Fin.ne_of_val_ne
        exact Nat.ne_of_lt (by assumption)
    rw [this, sf]
    apply inv.1 j.prev ij (by assumption)
Proof state after:
no goals
Theorem: partitionImpl.loop_invariant
Proof state before:
case inv₁
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
⊢ ∀ (k : Fin n), i.prev < k → k < j.prev → swapped[k] < swapped[first]
Tactic:
intro k ik kj
Proof state after:
case inv₁
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik : i.prev < k
kj : k < j.prev
⊢ swapped[k] < swapped[first]
Theorem: partitionImpl.loop_invariant
Proof state before:
case inv₁
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik : i.prev < k
kj : k < j.prev
⊢ swapped[k] < swapped[first]
Tactic:
have ik : i.val ≤ k.val := by
  rw [←Nat.sub_add_cancel (Nat.zero_lt_of_lt fi)]
  exact ik
Proof state after:
case inv₁
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik✝ : i.prev < k
kj : k < j.prev
ik : ↑i ≤ ↑k
⊢ swapped[k] < swapped[first]
Theorem: partitionImpl.loop_invariant
Proof state before:
case inv₁
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik✝ : i.prev < k
kj : k < j.prev
ik : ↑i ≤ ↑k
⊢ swapped[k] < swapped[first]
Tactic:
cases Nat.eq_or_lt_of_le ik with
| inl ik =>
  have : swapped[k] = arr[j] := by
    simp [Fin.eq_of_val_eq ik.symm]
    apply Vec.get_swap_left
  rw [this, sf]
  exact inv.3 (Nat.lt_of_lt_of_le (Fin.eq_of_val_eq ik.symm ▸ kj) (Nat.sub_le ..))
| inr ik =>
  have kj : k < j := (Nat.lt_of_lt_of_le kj (Nat.sub_le ..))
  have : swapped[k] = arr[k] := by
    apply Vec.get_swap_neq
    . apply Fin.ne_of_val_ne
      exact Nat.ne_of_gt ik
    . apply Fin.ne_of_val_ne
      exact Nat.ne_of_lt kj
  rw [this, sf]
  exact inv.1 k ik kj
Proof state after:
no goals
Theorem: partitionImpl.loop_invariant
Proof state before:
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik : i.prev < k
kj : k < j.prev
⊢ ↑i ≤ ↑k
Tactic:
rw [←Nat.sub_add_cancel (Nat.zero_lt_of_lt fi)]
Proof state after:
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik : i.prev < k
kj : k < j.prev
⊢ ↑i - Nat.succ 0 + Nat.succ 0 ≤ ↑k
Theorem: partitionImpl.loop_invariant
Proof state before:
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik : i.prev < k
kj : k < j.prev
⊢ ↑i - Nat.succ 0 + Nat.succ 0 ≤ ↑k
Tactic:
exact ik
Proof state after:
no goals
Theorem: partitionImpl.loop_invariant
Proof state before:
case inv₁.inl
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik✝¹ : i.prev < k
kj : k < j.prev
ik✝ : ↑i ≤ ↑k
ik : ↑i = ↑k
⊢ swapped[k] < swapped[first]
Tactic:
have : swapped[k] = arr[j] := by
  simp [Fin.eq_of_val_eq ik.symm]
  apply Vec.get_swap_left
Proof state after:
case inv₁.inl
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik✝¹ : i.prev < k
kj : k < j.prev
ik✝ : ↑i ≤ ↑k
ik : ↑i = ↑k
this : swapped[k] = arr[j]
⊢ swapped[k] < swapped[first]
Theorem: partitionImpl.loop_invariant
Proof state before:
case inv₁.inl
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik✝¹ : i.prev < k
kj : k < j.prev
ik✝ : ↑i ≤ ↑k
ik : ↑i = ↑k
this : swapped[k] = arr[j]
⊢ swapped[k] < swapped[first]
Tactic:
rw [this, sf]
Proof state after:
case inv₁.inl
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik✝¹ : i.prev < k
kj : k < j.prev
ik✝ : ↑i ≤ ↑k
ik : ↑i = ↑k
this : swapped[k] = arr[j]
⊢ arr[j] < arr[first]
Theorem: partitionImpl.loop_invariant
Proof state before:
case inv₁.inl
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik✝¹ : i.prev < k
kj : k < j.prev
ik✝ : ↑i ≤ ↑k
ik : ↑i = ↑k
this : swapped[k] = arr[j]
⊢ arr[j] < arr[first]
Tactic:
exact inv.3 (Nat.lt_of_lt_of_le (Fin.eq_of_val_eq ik.symm ▸ kj) (Nat.sub_le ..))
Proof state after:
no goals
Theorem: partitionImpl.loop_invariant
Proof state before:
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik✝¹ : i.prev < k
kj : k < j.prev
ik✝ : ↑i ≤ ↑k
ik : ↑i = ↑k
⊢ swapped[k] = arr[j]
Tactic:
simp [Fin.eq_of_val_eq ik.symm]
Proof state after:
α : Type
inst✝ : Ord α
n : Nat
first✝ i✝ j✝ last : Fin n
arr : Vec α n
first i j : Fin n
fi✝ : first ≤ i
ij : i ≤ j
fi : first < i
x✝² : ↑first ≤ ↑i - 1
x✝¹ : ¬arr[i] < arr[first]
x✝ : ↑i - 1 ≤ ↑j - 1
ih :
  LoopInvariant (arr.swap i j) first i.prev j.prev last →
    ∀ (result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n),
      partitionImpl (arr.swap i j) first i.prev j.prev x✝² x✝ = result →
        LoopInvariant result.snd first first ⟨↑result.fst.val, ⋯⟩ last
inv : LoopInvariant arr first i j last
swapped : Vec α n := arr.swap i j
sf : swapped[first] = arr[first]
result : { mid // first ≤ mid ∧ mid ≤ j.prev } × Vec α n := partitionImpl swapped first i.prev j.prev x✝² x✝
k : Fin n
ik✝¹ : i.prev < k
kj : k < j.prev
ik✝ : ↑i ≤ ↑k
ik : ↑i = ↑k
⊢ swapped[i] = arr[j]