mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
ih :
  cs.wordProd (alternatingWord i i' m) = (if Even m then 1 else cs.simple i') * (cs.simple i * cs.simple i') ^ (m / 2)
hm : Even m
h₁ : ¬Even (m + 1)
⊢ ¬Even (m + 1)

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
ih :
  cs.wordProd (alternatingWord i i' m) = (if Even m then 1 else cs.simple i') * (cs.simple i * cs.simple i') ^ (m / 2)
hm : Even m
h₁ : ¬Even (m + 1)
⊢ ¬Even (m + 1)
Module: Mathlib.GroupTheory.CoprodI

Goal state before:
pp: ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
i j : ι
w : Word M
m : M i
⊢ (⟨i, m⟩ ∈ w.toList.tail ∨ i ≠ j ∧ ∃ (h : w.toList ≠ []), w.toList.head h = ⟨i, m⟩) → ⟨i, m⟩ ∈ w.toList

Tactic:
]

Goal state after:
ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
i j : ι
w : Word M
m : M i
⊢ (⟨i, m⟩ ∈ w.toList.tail ∨ i ≠ j ∧ ∃ (h : w.toList ≠ []), w.toList.head h = ⟨i, m⟩) → ⟨i, m⟩ ∈ w.toList
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: case inl
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
⊢ 1 * (cs.simple i * cs.simple i') ^ (k * 2 / 2) = 1 * (cs.simple i' * cs.simple i) ^ ((↑(M.M i i') - k) * 2 / 2)

Tactic:
]

Goal state after:
case inl
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
⊢ 1 * (cs.simple i * cs.simple i') ^ (k * 2 / 2) = 1 * (cs.simple i' * cs.simple i) ^ ((↑(M.M i i') - k) * 2 / 2)
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: case inl
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
⊢ 1 * (cs.simple i * cs.simple i') ^ k = 1 * (cs.simple i' * cs.simple i) ^ ((↑(M.M i i') - k) * 2 / 2)

Tactic:
]

Goal state after:
case inl
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
⊢ 1 * (cs.simple i * cs.simple i') ^ k = 1 * (cs.simple i' * cs.simple i) ^ ((↑(M.M i i') - k) * 2 / 2)
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: case inl
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
⊢ 1 * (cs.simple i * cs.simple i') ^ k = 1 * (cs.simple i' * cs.simple i) ^ (↑(M.M i i') - k)

Tactic:
]

Goal state after:
case inl
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
⊢ 1 * (cs.simple i * cs.simple i') ^ k = 1 * (cs.simple i' * cs.simple i) ^ (↑(M.M i i') - k)
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: case inl
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
⊢ 1 * (cs.simple i * cs.simple i') ^ k = 1 * (1 * (cs.simple i' * cs.simple i)⁻¹ ^ k)

Tactic:
]

Goal state after:
case inl
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
⊢ 1 * (cs.simple i * cs.simple i') ^ k = 1 * (1 * (cs.simple i' * cs.simple i)⁻¹ ^ k)
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this : ¬Even (2 * k + 1)
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ ((2 * k + 1) / 2) =
    (if Even (↑(M.M i i') * 2 - (2 * k + 1)) then 1 else cs.simple i) *
      (cs.simple i' * cs.simple i) ^ ((↑(M.M i i') * 2 - (2 * k + 1)) / 2)

Tactic:
]

Goal state after:
case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this : ¬Even (2 * k + 1)
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ ((2 * k + 1) / 2) =
    (if Even (↑(M.M i i') * 2 - (2 * k + 1)) then 1 else cs.simple i) *
      (cs.simple i' * cs.simple i) ^ ((↑(M.M i i') * 2 - (2 * k + 1)) / 2)
Module: Mathlib.GroupTheory.CoprodI

Goal state before:
pp: ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
i : ι
m : M i
w : Word M
⊢ (equivPair i)
      ((equivPair i).symm
        (have __src := (equivPair i) w;
        { head := m * ((equivPair i) w).head, tail := __src.tail, fstIdx_ne := ⋯ })) =
    { head := m * ((equivPair i) w).head, tail := ((equivPair i) w).tail, fstIdx_ne := ⋯ }

Tactic:
]

Goal state after:
ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
i : ι
m : M i
w : Word M
⊢ (equivPair i)
      ((equivPair i).symm
        (have __src := (equivPair i) w;
        { head := m * ((equivPair i) w).head, tail := __src.tail, fstIdx_ne := ⋯ })) =
    { head := m * ((equivPair i) w).head, tail := ((equivPair i) w).tail, fstIdx_ne := ⋯ }
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this : ¬Even (2 * k + 1)
⊢ ↑(M.M i i') * 2 - (2 * k + 1) = 2 * (↑(M.M i i') - k - 1) + 1

Tactic:
by ring

Goal state after:
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ ((2 * k + 1) / 2) =
    cs.simple i * (cs.simple i' * cs.simple i) ^ ((↑(M.M i i') * 2 - (2 * k + 1)) / 2)

Tactic:
]

Goal state after:
case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ ((2 * k + 1) / 2) =
    cs.simple i * (cs.simple i' * cs.simple i) ^ ((↑(M.M i i') * 2 - (2 * k + 1)) / 2)
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ ↑(M.M i i') * 2 - (2 * k + 1) = -1 + (-k + ↑(M.M i i')) * 2

Tactic:
by ring

Goal state after:
Module: Mathlib.GroupTheory.CoprodI

Goal state before:
pp: ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
i j : ι
m₁ : M i
m₂ : M j
w : Word M
⊢ (⟨i, m₁⟩ ∈ w.toList.tail ∨
      (i ≠ j ∧ ∃ (h : w.toList ≠ []), w.toList.head h = ⟨i, m₁⟩) ∨
        m₁ ≠ 1 ∧
          ∃ (h : j = i),
            m₁ =
              h ▸
                (have __src := (equivPair j) w;
                  {
                    head :=
                      m₂ *
                        if h : ∃ (h : w.toList ≠ []), (w.toList.head h).fst = j then ⋯ ▸ (w.toList.head ⋯).snd else 1,
                    tail := __src.tail, fstIdx_ne := ⋯ }).head) ↔
    ¬i = j ∧ ⟨i, m₁⟩ ∈ w.toList ∨
      m₁ ≠ 1 ∧
        ∃ (hij : i = j),
          ⟨i, m₁⟩ ∈ w.toList.tail ∨
            (∃ m', ⟨j, m'⟩ ∈ w.toList.head? ∧ m₁ = ⋯ ▸ (m₂ * m')) ∨ w.fstIdx ≠ some j ∧ m₁ = ⋯ ▸ m₂

Tactic:
]

Goal state after:
ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
i j : ι
m₁ : M i
m₂ : M j
w : Word M
⊢ (⟨i, m₁⟩ ∈ w.toList.tail ∨
      (i ≠ j ∧ ∃ (h : w.toList ≠ []), w.toList.head h = ⟨i, m₁⟩) ∨
        m₁ ≠ 1 ∧
          ∃ (h : j = i),
            m₁ =
              h ▸
                (have __src := (equivPair j) w;
                  {
                    head :=
                      m₂ *
                        if h : ∃ (h : w.toList ≠ []), (w.toList.head h).fst = j then ⋯ ▸ (w.toList.head ⋯).snd else 1,
                    tail := __src.tail, fstIdx_ne := ⋯ }).head) ↔
    ¬i = j ∧ ⟨i, m₁⟩ ∈ w.toList ∨
      m₁ ≠ 1 ∧
        ∃ (hij : i = j),
          ⟨i, m₁⟩ ∈ w.toList.tail ∨
            (∃ m', ⟨j, m'⟩ ∈ w.toList.head? ∧ m₁ = ⋯ ▸ (m₂ * m')) ∨ w.fstIdx ≠ some j ∧ m₁ = ⋯ ▸ m₂
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ 2 * k + 1 = 1 + k * 2

Tactic:
by ring

Goal state after:
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ ((1 + k * 2) / 2) =
    cs.simple i * (cs.simple i' * cs.simple i) ^ ((-1 + (-k + ↑(M.M i i')) * 2) / 2)

Tactic:
]

Goal state after:
case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ ((1 + k * 2) / 2) =
    cs.simple i * (cs.simple i' * cs.simple i) ^ ((-1 + (-k + ↑(M.M i i')) * 2) / 2)
Module: Mathlib.Topology.VectorBundle.Riemannian

Goal state before:
pp: B : Type u_1
inst✝⁷ : TopologicalSpace B
F : Type u_2
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace ℝ F
E : B → Type u_3
inst✝⁴ : TopologicalSpace (TotalSpace F E)
inst✝³ : (x : B) → NormedAddCommGroup (E x)
inst✝² : (x : B) → InnerProductSpace ℝ (E x)
inst✝¹ : FiberBundle F E
inst✝ : VectorBundle ℝ F E
h : IsContinuousRiemannianBundle F E
x : B
r : ℝ
hr : 1 < r
r' : ℝ
hr' : 1 < r'
r'r : r' < r
h'x : x ∈ (trivializationAt F E x).baseSet
G : E x ≃L[ℝ] F := Trivialization.continuousLinearEquivAt ℝ (trivializationAt F E x) x h'x
C : ℝ := ‖↑G‖ ^ 2
δ : ℝ
δpos : 0 < δ
h'δ : 1 + δ * C < r' ^ 2
g : (x : B) → E x →L[ℝ] E x →L[ℝ] ℝ
g_cont :
  Continuous[inst✝⁷, topologicalSpaceTotalSpace (RingHom.id ℝ) F E (F →L[ℝ] ℝ) fun x ↦ E x →L[ℝ] ℝ] fun x ↦
    TotalSpace.mk' (F →L[ℝ] F →L[ℝ] ℝ) x (g x)
hg : ∀ (x : B) (v w : E x), ⟪v, w⟫ = ((g x) v) w
g' : B → F →L[ℝ] F →L[ℝ] ℝ := fun y ↦ inCoordinates F E (F →L[ℝ] ℝ) (fun x ↦ E x →L[ℝ] ℝ) x y x y (g y)
hg' : ∀ ε > 0, ∀ᶠ (x_1 : B) in 𝓝 x, dist (g' x_1) (g' x) < ε
⊢ ∀ᶠ (y : B) in 𝓝 x, dist (g' y) (g' x) < δ

Tactic:
]

Goal state after:
B : Type u_1
inst✝⁷ : TopologicalSpace B
F : Type u_2
inst✝⁶ : NormedAddCommGroup F
inst✝⁵ : NormedSpace ℝ F
E : B → Type u_3
inst✝⁴ : TopologicalSpace (TotalSpace F E)
inst✝³ : (x : B) → NormedAddCommGroup (E x)
inst✝² : (x : B) → InnerProductSpace ℝ (E x)
inst✝¹ : FiberBundle F E
inst✝ : VectorBundle ℝ F E
h : IsContinuousRiemannianBundle F E
x : B
r : ℝ
hr : 1 < r
r' : ℝ
hr' : 1 < r'
r'r : r' < r
h'x : x ∈ (trivializationAt F E x).baseSet
G : E x ≃L[ℝ] F := Trivialization.continuousLinearEquivAt ℝ (trivializationAt F E x) x h'x
C : ℝ := ‖↑G‖ ^ 2
δ : ℝ
δpos : 0 < δ
h'δ : 1 + δ * C < r' ^ 2
g : (x : B) → E x →L[ℝ] E x →L[ℝ] ℝ
g_cont :
  Continuous[inst✝⁷, topologicalSpaceTotalSpace (RingHom.id ℝ) F E (F →L[ℝ] ℝ) fun x ↦ E x →L[ℝ] ℝ] fun x ↦
    TotalSpace.mk' (F →L[ℝ] F →L[ℝ] ℝ) x (g x)
hg : ∀ (x : B) (v w : E x), ⟪v, w⟫ = ((g x) v) w
g' : B → F →L[ℝ] F →L[ℝ] ℝ := fun y ↦ inCoordinates F E (F →L[ℝ] ℝ) (fun x ↦ E x →L[ℝ] ℝ) x y x y (g y)
hg' : ∀ ε > 0, ∀ᶠ (x_1 : B) in 𝓝 x, dist (g' x_1) (g' x) < ε
⊢ ∀ᶠ (y : B) in 𝓝 x, dist (g' y) (g' x) < δ
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ (1 / 2 + k) =
    cs.simple i * (cs.simple i' * cs.simple i) ^ ((-1 + (-k + ↑(M.M i i')) * 2) / 2)

Tactic:
]

Goal state after:
case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ (1 / 2 + k) =
    cs.simple i * (cs.simple i' * cs.simple i) ^ ((-1 + (-k + ↑(M.M i i')) * 2) / 2)
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ (1 / 2 + k) =
    cs.simple i * (cs.simple i' * cs.simple i) ^ (-1 / 2 + (-k + ↑(M.M i i')))

Tactic:
]

Goal state after:
case inr
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
m : ℕ
k : ℤ
this✝ : ¬Even (2 * k + 1)
this : ¬Even (↑(M.M i i') * 2 - (2 * k + 1))
⊢ cs.simple i' * (cs.simple i * cs.simple i') ^ (1 / 2 + k) =
    cs.simple i * (cs.simple i' * cs.simple i) ^ (-1 / 2 + (-k + ↑(M.M i i')))
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: case mp
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
ω : List B
hω : cs.IsReduced ω
h : cs.length (cs.wordProd ω) = 0
this : ω = []
⊢ 1 = 1

Tactic:
]

Goal state after:
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: case h₁
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
ω : List B
hω : cs.IsReduced ω
this : cs.length (cs.wordProd ω)⁻¹ ≤ cs.length (cs.wordProd ω)
⊢ cs.length (cs.wordProd ω)⁻¹ ≤ cs.length (cs.wordProd ω)

Tactic:
]

Goal state after:
case h₁
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
ω : List B
hω : cs.IsReduced ω
this : cs.length (cs.wordProd ω)⁻¹ ≤ cs.length (cs.wordProd ω)
⊢ cs.length (cs.wordProd ω)⁻¹ ≤ cs.length (cs.wordProd ω)
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: case h₂
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
ω : List B
hω : cs.IsReduced ω
h'ω : w⁻¹ = cs.wordProd ω
this : cs.length w ≤ cs.length w⁻¹
⊢ cs.length w ≤ cs.length w⁻¹

Tactic:
]

Goal state after:
case h₂
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
ω : List B
hω : cs.IsReduced ω
h'ω : w⁻¹ = cs.wordProd ω
this : cs.length w ≤ cs.length w⁻¹
⊢ cs.length w ≤ cs.length w⁻¹
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
this : cs.wordProd (alternatingWord i i' (M.M i i')) = cs.wordProd (alternatingWord i' i (M.M i i'))
⊢ cs.wordProd (braidWord M i i') = cs.wordProd (braidWord M i' i)

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
this : cs.wordProd (alternatingWord i i' (M.M i i')) = cs.wordProd (alternatingWord i' i (M.M i i'))
⊢ cs.wordProd (braidWord M i i') = cs.wordProd (braidWord M i' i)
Module: Mathlib.GroupTheory.Coxeter.Basic

Goal state before:
pp: B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
this : cs.wordProd (alternatingWord i i' (M.M i i')) = cs.wordProd (alternatingWord i' i (M.M i' i))
⊢ cs.wordProd (braidWord M i i') = cs.wordProd (braidWord M i' i)

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_3
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i i' : B
this : cs.wordProd (alternatingWord i i' (M.M i i')) = cs.wordProd (alternatingWord i' i (M.M i' i))
⊢ cs.wordProd (braidWord M i i') = cs.wordProd (braidWord M i' i)
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w₁ w₂ : W
⊢ cs.length w₁ ≤ cs.length (w₁ * w₂) + cs.length w₂

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w₁ w₂ : W
⊢ cs.length w₁ ≤ cs.length (w₁ * w₂) + cs.length w₂
Module: Mathlib.GroupTheory.Coxeter.Inversion

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
t : W
ht : cs.IsReflection t
⊢ cs.IsReflection t

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
t : W
ht : cs.IsReflection t
⊢ cs.IsReflection t
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w₁ w₂ : W
⊢ cs.length w₂ ≤ cs.length (w₁ * w₂) + cs.length w₁

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w₁ w₂ : W
⊢ cs.length w₂ ≤ cs.length (w₁ * w₂) + cs.length w₁
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
ω : List B
hω : cs.IsReduced ω
⊢ Multiplicative.ofAdd ↑ω.length = Multiplicative.ofAdd ↑ω.length

Tactic:
]

Goal state after:
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w₁ w₂ : W
⊢ ↑(cs.length (w₁ * w₂)) = ↑(cs.length w₁) + ↑(cs.length w₂)

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w₁ w₂ : W
⊢ ↑(cs.length (w₁ * w₂)) = ↑(cs.length w₁) + ↑(cs.length w₂)
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
i : B
length_lt_one : cs.length (cs.simple i) < 1
⊢ Multiplicative.ofAdd 0 = Multiplicative.ofAdd 0

Tactic:
]

Goal state after:
Module: Mathlib.GroupTheory.CoprodI

Goal state before:
pp: ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
w : Word M
hnil : ¬w.toList = []
m₂ m₁ : M (w.toList.head hnil).fst
hw : ⟨(w.toList.head hnil).fst, m₁⟩ ∉ w.toList.tail
hm1 : ¬m₁ = 1
hm' : (∀ (x : M (w.toList.head hnil).fst), ¬w.toList.head? = some ⟨(w.toList.head hnil).fst, x⟩) ∧ m₁ = m₂
⊢ some (w.toList.head ?m.280) = some ⟨(w.toList.head hnil).fst, (w.toList.head hnil).snd⟩

pp: ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
w : Word M
hnil : ¬w.toList = []
m₂ m₁ : M (w.toList.head hnil).fst
hw : ⟨(w.toList.head hnil).fst, m₁⟩ ∉ w.toList.tail
hm1 : ¬m₁ = 1
hm' : (∀ (x : M (w.toList.head hnil).fst), ¬w.toList.head? = some ⟨(w.toList.head hnil).fst, x⟩) ∧ m₁ = m₂
⊢ w.toList ≠ []

Tactic:
]

Goal state after:
Module: Mathlib.GroupTheory.Coxeter.Inversion

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w t : W
ht : cs.IsReflection t
⊢ cs.length (t * w) < cs.length w ↔ cs.length (t * w) < cs.length w

Tactic:
]

Goal state after:
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
eq : cs.length (w * cs.simple i) = cs.length w
length_mod_two : cs.length w % 2 = (cs.length w + 1) % 2
⊢ False

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
eq : cs.length (w * cs.simple i) = cs.length w
length_mod_two : cs.length w % 2 = (cs.length w + 1) % 2
⊢ False
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
⊢ cs.length (cs.simple i * w)⁻¹ ≠ cs.length w

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
⊢ cs.length (cs.simple i * w)⁻¹ ≠ cs.length w
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: case inl
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
h : cs.length (w * cs.simple i) + 1 ≤ cs.length w
⊢ cs.length (w * cs.simple i) = cs.length w + 1 ∨ cs.length (w * cs.simple i) + 1 = cs.length w

Tactic:
]

Goal state after:
case inl
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
h : cs.length (w * cs.simple i) + 1 ≤ cs.length w
⊢ cs.length (w * cs.simple i) = cs.length w + 1 ∨ cs.length (w * cs.simple i) + 1 = cs.length w
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: case inr
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
h : cs.length w + 1 ≤ cs.length (w * cs.simple i)
⊢ cs.length (w * cs.simple i) = cs.length w + 1 ∨ cs.length (w * cs.simple i) + 1 = cs.length w

Tactic:
]

Goal state after:
case inr
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
h : cs.length w + 1 ≤ cs.length (w * cs.simple i)
⊢ cs.length (w * cs.simple i) = cs.length w + 1 ∨ cs.length (w * cs.simple i) + 1 = cs.length w
Module: Mathlib.GroupTheory.Coxeter.Inversion

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
t : W
ht : cs.IsReflection t
w : W
⊢ ¬cs.IsRightInversion w⁻¹ t ↔ ¬cs.IsRightInversion w⁻¹ t

Tactic:
]

Goal state after:
Module: Mathlib.GroupTheory.CoprodI

Goal state before:
pp: case neg
ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
j : ι
m₂ : M j
w : Word M
m₁ : M j
hw : ⟨j, m₁⟩ ∉ w.toList.tail
hm1 : ¬m₁ = 1
⊢ (¬∃ (h : ¬w.toList = []), (w.toList.head h).fst = j) →
    (m₁ = m₂ * 1 ↔
      (∃ m', w.toList.head? = some ⟨j, m'⟩ ∧ m₁ = m₂ * m') ∨ ¬Option.map Sigma.fst w.toList.head? = some j ∧ m₁ = m₂)

Tactic:
]

Goal state after:
case neg
ι : Type u_1
M : ι → Type u_2
inst✝² : (i : ι) → Monoid (M i)
inst✝¹ : DecidableEq ι
inst✝ : (i : ι) → DecidableEq (M i)
j : ι
m₂ : M j
w : Word M
m₁ : M j
hw : ⟨j, m₁⟩ ∉ w.toList.tail
hm1 : ¬m₁ = 1
⊢ (¬∃ (h : ¬w.toList = []), (w.toList.head h).fst = j) →
    (m₁ = m₂ * 1 ↔
      (∃ m', w.toList.head? = some ⟨j, m'⟩ ∧ m₁ = m₂ * m') ∨ ¬Option.map Sigma.fst w.toList.head? = some j ∧ m₁ = m₂)
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
this : cs.length (cs.simple i * w) = cs.length w + 1 ∨ cs.length (cs.simple i * w) + 1 = cs.length w
⊢ cs.length (cs.simple i * w) = cs.length w + 1 ∨ cs.length (cs.simple i * w) + 1 = cs.length w

Tactic:
]

Goal state after:
B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
w : W
i : B
this : cs.length (cs.simple i * w) = cs.length w + 1 ∨ cs.length (cs.simple i * w) + 1 = cs.length w
⊢ cs.length (cs.simple i * w) = cs.length w + 1 ∨ cs.length (cs.simple i * w) + 1 = cs.length w
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
ω : List B
hω : cs.IsReduced ω
j : ℕ
h₁ : cs.length (cs.wordProd (take j ω)) ≤ (take j ω).length
h₂ : cs.length (cs.wordProd (drop j ω)) ≤ (drop j ω).length
⊢ ω.length = ω.length

Tactic:
]

Goal state after:
Module: Mathlib.GroupTheory.Coxeter.Length

Goal state before:
pp: B : Type u_1
W : Type u_2
inst✝ : Group W
M : CoxeterMatrix B
cs : CoxeterSystem M W
ω : List B
hω : cs.IsReduced ω
j : ℕ
h₁ : cs.length (cs.wordProd (take j ω)) ≤ (take j ω).length
h₂ : cs.length (cs.wordProd (drop j ω)) ≤ (drop j ω).length
⊢ cs.length (cs.wordProd ω) = cs.length (cs.wordProd ω)

Tactic:
]

Goal state after: