l3lab/ntp-mathlib huggingface dataset:
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => 

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
| ∃ g, g 0 • Matrix.vecCons x ![r • x + y] 0 + g 1 • Matrix.vecCons x ![r • x + y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => 

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
| ∃ g, g 0 • Matrix.vecCons x ![r • x + y] 0 + g 1 • Matrix.vecCons x ![r • x + y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
enter [1, g, 2, 1, i]
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; 

Proof state:
case h.h
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
g : Fin (Nat.succ (Nat.succ 0)) → ℝ
i : Fin (Nat.succ (Nat.succ 0))
| g i ≠ 0

Next tactic:
tactic => change Fin 2 at i
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => 

Proof state:
case h.h
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
g : Fin (Nat.succ (Nat.succ 0)) → ℝ
i : Fin (Nat.succ (Nat.succ 0))
⊢ (g i ≠ 0) = ?m.780696 g i

Next tactic:
change Fin 2 at i
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
⊢ (∃ g, g 0 • Matrix.vecCons x ![r • x + y] 0 + g 1 • Matrix.vecCons x ![r • x + y] 1 = 0 ∧ ∃ i, g i ≠ 0) ↔
    ∃ g, g 0 • Matrix.vecCons x ![y] 0 + g 1 • Matrix.vecCons x ![y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
conv_lhs => enter [1, g]; rw [Fin.exists_fin_two]
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => 

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
| ∃ g, g 0 • Matrix.vecCons x ![r • x + y] 0 + g 1 • Matrix.vecCons x ![r • x + y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
enter [1, g]; rw [Fin.exists_fin_two]
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => 

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
| ∃ g, g 0 • Matrix.vecCons x ![r • x + y] 0 + g 1 • Matrix.vecCons x ![r • x + y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
enter [1, g]
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; 

Proof state:
case h
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
g : Fin (Nat.succ (Nat.succ 0)) → ℝ
| g 0 • Matrix.vecCons x ![r • x + y] 0 + g 1 • Matrix.vecCons x ![r • x + y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
rw [Fin.exists_fin_two]
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.exists_fin_two]
  

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
⊢ (∃ g, g 0 • Matrix.vecCons x ![r • x + y] 0 + g 1 • Matrix.vecCons x ![r • x + y] 1 = 0 ∧ (g 0 ≠ 0 ∨ g 1 ≠ 0)) ↔
    ∃ g, g 0 • Matrix.vecCons x ![y] 0 + g 1 • Matrix.vecCons x ![y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
conv_rhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.exists_fin_two]
  conv_rhs => 

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
| ∃ g, g 0 • Matrix.vecCons x ![y] 0 + g 1 • Matrix.vecCons x ![y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.exists_fin_two]
  conv_rhs => 

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
| ∃ g, g 0 • Matrix.vecCons x ![y] 0 + g 1 • Matrix.vecCons x ![y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
enter [1, g, 2, 1, i]
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.exists_fin_two]
  conv_rhs => enter [1, g, 2, 1, i]; 

Proof state:
case h.h
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
g : Fin (Nat.succ (Nat.succ 0)) → ℝ
i : Fin (Nat.succ (Nat.succ 0))
| g i ≠ 0

Next tactic:
tactic => change Fin 2 at i
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.exists_fin_two]
  conv_rhs => enter [1, g, 2, 1, i]; tactic => 

Proof state:
case h.h
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
g : Fin (Nat.succ (Nat.succ 0)) → ℝ
i : Fin (Nat.succ (Nat.succ 0))
⊢ (g i ≠ 0) = ?m.805592 g i

Next tactic:
change Fin 2 at i
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.exists_fin_two]
  conv_rhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
⊢ (∃ g, g 0 • Matrix.vecCons x ![r • x + y] 0 + g 1 • Matrix.vecCons x ![r • x + y] 1 = 0 ∧ (g 0 ≠ 0 ∨ g 1 ≠ 0)) ↔
    ∃ g, g 0 • Matrix.vecCons x ![y] 0 + g 1 • Matrix.vecCons x ![y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
conv_rhs => enter [1, g]; rw [Fin.exists_fin_two]
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.exists_fin_two]
  conv_rhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_rhs => 

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
| ∃ g, g 0 • Matrix.vecCons x ![y] 0 + g 1 • Matrix.vecCons x ![y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
enter [1, g]; rw [Fin.exists_fin_two]
/-- Auxiliary lemma for the proof of `oangle_sign_smul_add_right`; not intended to be used
outside of that proof. -/
theorem oangle_smul_add_right_eq_zero_or_eq_pi_iff {x y : V} (r : ℝ) :
    o.oangle x (r • x + y) = 0 ∨ o.oangle x (r • x + y) = π ↔
    o.oangle x y = 0 ∨ o.oangle x y = π := by
  simp_rw [oangle_eq_zero_or_eq_pi_iff_not_linearIndependent, Fintype.not_linearIndependent_iff]
  -- Porting note: at this point all occurences of the bound variable `i` are of type
  -- `Fin (Nat.succ (Nat.succ 0))`, but `Fin.sum_univ_two` and `Fin.exists_fin_two` expect it to be
  -- `Fin 2` instead. Hence all the `conv`s.
  -- Was `simp_rw [Fin.sum_univ_two, Fin.exists_fin_two]`
  conv_lhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_rhs => enter [1, g, 1, 1, 2, i]; tactic => change Fin 2 at i
  conv_rhs => enter [1, g]; rw [Fin.sum_univ_two]
  conv_lhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_lhs => enter [1, g]; rw [Fin.exists_fin_two]
  conv_rhs => enter [1, g, 2, 1, i]; tactic => change Fin 2 at i
  conv_rhs => 

Proof state:
V : Type u_1
V' : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : NormedAddCommGroup V'
inst✝³ : InnerProductSpace ℝ V
inst✝² : InnerProductSpace ℝ V'
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Fact (finrank ℝ V' = 2)
o : Orientation ℝ V (Fin 2)
x y : V
r : ℝ
| ∃ g, g 0 • Matrix.vecCons x ![y] 0 + g 1 • Matrix.vecCons x ![y] 1 = 0 ∧ ∃ i, g i ≠ 0

Next tactic:
enter [1, g]