mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Geometry.Euclidean.Angle.Bisector

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p p₁ p₂ p₃ : P
ha : AffineIndependent ℝ ![p₁, p₂, p₃]
h : dist p ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = dist p ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
⊢ 2 • ∡ p₂ p₁ p = 2 • ∡ p p₁ p₃

Tactic:
by_cases ho : (orthogonalProjection line[ℝ, p₁, p₂] p : P) =
      orthogonalProjection line[ℝ, p₁, p₃] p

Goal state after:
case pos
V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p p₁ p₂ p₃ : P
ha : AffineIndependent ℝ ![p₁, p₂, p₃]
h : dist p ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = dist p ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
ho : ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
⊢ 2 • ∡ p₂ p₁ p = 2 • ∡ p p₁ p₃

case neg
V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p p₁ p₂ p₃ : P
ha : AffineIndependent ℝ ![p₁, p₂, p₃]
h : dist p ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = dist p ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
ho : ¬↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
⊢ 2 • ∡ p₂ p₁ p = 2 • ∡ p p₁ p₃
Module: Mathlib.Geometry.Euclidean.Sphere.Tangent

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Sphere P
as : AffineSubspace ℝ P
p : P
hp : p ∈ as
x : P
h : s.IsTangentAt x as
⊢ s.radius ^ 2 ≤ s.radius ^ 2 + dist p x ^ 2

Tactic:
le_add_iff_nonneg_right

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Sphere P
as : AffineSubspace ℝ P
p : P
hp : p ∈ as
x : P
h : s.IsTangentAt x as
⊢ 0 ≤ dist p x ^ 2
Module: Mathlib.Geometry.Euclidean.Sphere.Tangent

Goal state before:
pp: case inr.inr.inr
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Sphere P
p : P
hp : p ∈ s
q : P
hqs : q ∈ s
hrad : s.radius ≠ 0
hpar : s.orthRadius q ∥ s.orthRadius p
hqas : q ∈ s.orthRadius q
hqo : s.orthRadius q ≤ s.orthRadius q
hr : q -ᵥ s.center = -1 • (p -ᵥ s.center)
hr0 : -1 ≠ 0
hr' : |(-1)| = 1
⊢ s.orthRadius q = s.orthRadius p ∨ s.orthRadius q = s.orthRadius ((Equiv.pointReflection s.center) p)

Tactic:
right
      convert! rfl
      rw [← eq_vadd_iff_vsub_eq] at hr
      rw [hr]
      simp [Equiv.pointReflection_apply]

Goal state after:
Module: Mathlib.Geometry.Euclidean.Sphere.OrthRadius

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
hf2 : Fact (Module.finrank ℝ V = 2)
s : Sphere P
p : P
hp : dist p s.center ≤ s.radius
hpc : p ≠ s.center
v : V
hv : v ∈ (ℝ ∙ (p -ᵥ s.center))ᗮ
hv1 : ‖v‖ = 1
hr : 0 ≤ s.radius
hv0 : v ≠ 0
⊢ Metric.sphere s.center s.radius ∩ ↑(s.orthRadius p) =
    {√(s.radius ^ 2 - dist p s.center ^ 2) • v +ᵥ p, -(√(s.radius ^ 2 - dist p s.center ^ 2) • v) +ᵥ p}

Tactic:
have hf := finrank_orthRadius hpc

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
hf2 : Fact (Module.finrank ℝ V = 2)
s : Sphere P
p : P
hp : dist p s.center ≤ s.radius
hpc : p ≠ s.center
v : V
hv : v ∈ (ℝ ∙ (p -ᵥ s.center))ᗮ
hv1 : ‖v‖ = 1
hr : 0 ≤ s.radius
hv0 : v ≠ 0
hf : Module.finrank ℝ ↥(s.orthRadius p).direction + 1 = Module.finrank ℝ V
⊢ Metric.sphere s.center s.radius ∩ ↑(s.orthRadius p) =
    {√(s.radius ^ 2 - dist p s.center ^ 2) • v +ᵥ p, -(√(s.radius ^ 2 - dist p s.center ^ 2) • v) +ᵥ p}
Module: Mathlib.Geometry.Euclidean.Sphere.OrthRadius

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
hf2 : Fact (Module.finrank ℝ V = 2)
s : Sphere P
p : P
hp : dist p s.center < s.radius
hpc : p ≠ s.center
⊢ (Metric.sphere s.center s.radius ∩ ↑(s.orthRadius p)).ncard = 2

Tactic:
have hf := finrank_orthRadius hpc

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
hf2 : Fact (Module.finrank ℝ V = 2)
s : Sphere P
p : P
hp : dist p s.center < s.radius
hpc : p ≠ s.center
hf : Module.finrank ℝ ↥(s.orthRadius p).direction + 1 = Module.finrank ℝ V
⊢ (Metric.sphere s.center s.radius ∩ ↑(s.orthRadius p)).ncard = 2
Module: Mathlib.Geometry.Euclidean.Angle.Sphere

Goal state before:
pp: V : Type u_1
inst✝² : NormedAddCommGroup V
inst✝¹ : InnerProductSpace ℝ V
inst✝ : Fact (finrank ℝ V = 2)
o : Orientation ℝ V (Fin 2)
x y z : V
hxyne : x ≠ y
hxzne : x ≠ z
hxy : ‖x‖ = ‖y‖
hxz : ‖x‖ = ‖z‖
⊢ o.oangle y z = 2 • o.oangle (y - x) (z - x)

Tactic:
have hy : y ≠ 0 := by
    rintro rfl
    rw [norm_zero, norm_eq_zero] at hxy
    exact hxyne hxy

Goal state after:
V : Type u_1
inst✝² : NormedAddCommGroup V
inst✝¹ : InnerProductSpace ℝ V
inst✝ : Fact (finrank ℝ V = 2)
o : Orientation ℝ V (Fin 2)
x y z : V
hxyne : x ≠ y
hxzne : x ≠ z
hxy : ‖x‖ = ‖y‖
hxz : ‖x‖ = ‖z‖
hy : y ≠ 0
⊢ o.oangle y z = 2 • o.oangle (y - x) (z - x)
Module: Mathlib.Geometry.Euclidean.Angle.Sphere

Goal state before:

Tactic:
o.oangle y z = o.oangle x z - o.oangle x y := (o.oangle_sub_left hx hy hz).symm
    _ = π - (2 : ℤ) • o.oangle (x - z) x - (π - (2 : ℤ) • o.oangle (x - y) x) := by
      rw [o.oangle_eq_pi_sub_two_zsmul_oangle_sub_of_norm_eq hxzne.symm hxz.symm,
        o.oangle_eq_pi_sub_two_zsmul_oangle_sub_of_norm_eq hxyne.symm hxy.symm]
    _ = (2 : ℤ) • (o.oangle (x - y) x - o.oangle (x - z) x) := by abel
    _ = (2 : ℤ) • o.oangle (x - y) (x - z) := by
      rw [o.oangle_sub_right (sub_ne_zero_of_ne hxyne) (sub_ne_zero_of_ne hxzne) hx]
    _ = (2 : ℤ) • o.oangle (y - x) (z - x) := by rw [← oangle_neg_neg, neg_sub, neg_sub]

Goal state after:
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
⊢ (s.reindex e).exsphere ∅ = s.exsphere ∅

Tactic:
exsphere_reindex

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
⊢ s.exsphere (Finset.map e.symm.toEmbedding ∅) = s.exsphere ∅
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
signs : Finset (Fin (m + 1))
⊢ ((s.reindex e).exsphere signs).center = (s.exsphere (Finset.map e.symm.toEmbedding signs)).center

Tactic:
exsphere_reindex

Goal state after:
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
⊢ ((s.reindex e).exsphere ∅).center = (s.exsphere ∅).center

Tactic:
exsphere_reindex

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
⊢ (s.exsphere (Finset.map e.symm.toEmbedding ∅)).center = (s.exsphere ∅).center
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
signs : Finset (Fin (m + 1))
⊢ ((s.reindex e).exsphere signs).radius = (s.exsphere (Finset.map e.symm.toEmbedding signs)).radius

Tactic:
exsphere_reindex

Goal state after:
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
⊢ ((s.reindex e).exsphere ∅).radius = (s.exsphere ∅).radius

Tactic:
exsphere_reindex

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
⊢ (s.exsphere (Finset.map e.symm.toEmbedding ∅)).radius = (s.exsphere ∅).radius
Module: Mathlib.Geometry.Euclidean.Angle.Sphere

Goal state before:
pp: V : Type u_3
P : Type u_4
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
s : Sphere P
p₁ p₂ p₃ : P
hp₁ : p₁ ∈ s
hp₂ : p₂ ∈ s
hp₃ : p₃ ∈ s
hp₁p₂ : p₁ ≠ p₂
hp₁p₃ : p₁ ≠ p₃
hp₂p₃ : p₂ ≠ p₃
⊢ dist p₁ p₃ / |(∡ p₁ p₂ p₃).sin| / 2 = s.radius

Tactic:
by
  convert! dist_div_cos_oangle_center_div_two_eq_radius hp₁ hp₃ hp₁p₃
  rw [← Real.Angle.abs_cos_eq_abs_sin_of_two_zsmul_add_two_zsmul_eq_pi
    (two_zsmul_oangle_center_add_two_zsmul_oangle_eq_pi hp₁ hp₂ hp₃ hp₁p₂.symm hp₂p₃ hp₁p₃),
    abs_of_nonneg (Real.Angle.cos_nonneg_iff_abs_toReal_le_pi_div_two.2 _)]
  exact (abs_oangle_center_right_toReal_lt_pi_div_two hp₁ hp₃).le

Goal state after:
Module: Mathlib.Geometry.Euclidean.Triangle

Goal state before:
pp: case inr
V : Type u_1
inst✝¹ : NormedAddCommGroup V
inst✝ : InnerProductSpace ℝ V
x y : V
hy : y ≠ 0
hx : x ≠ 0
h✝ : ↑(angle x y) = ↑(angle x (x + y) + angle y (x + y))
n : ℤ
h : angle x y + n • (2 * π) = angle x (x + y) + angle y (x + y)
this✝ : -1 < n
this : n < 1
⊢ angle x y = angle x (x + y) + angle y (x + y)

Tactic:
obtain rfl : n = 0 := by lia

Goal state after:
case inr
V : Type u_1
inst✝¹ : NormedAddCommGroup V
inst✝ : InnerProductSpace ℝ V
x y : V
hy : y ≠ 0
hx : x ≠ 0
h✝ : ↑(angle x y) = ↑(angle x (x + y) + angle y (x + y))
h : angle x y + 0 • (2 * π) = angle x (x + y) + angle y (x + y)
this✝ : -1 < 0
this : 0 < 1
⊢ angle x y = angle x (x + y) + angle y (x + y)
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
signs : Finset (Fin (n + 1))
r : ℝ
w : Fin (n + 1) → ℝ
h1 : ∑ i, w i = 1
hp : (Finset.affineCombination ℝ Finset.univ s.points) w ∈ affineSpan ℝ (Set.range s.points)
h :
  ∀ (i : Fin (n + 1)),
    (s.signedInfDist i) ((Finset.affineCombination ℝ Finset.univ s.points) w) = (if i ∈ signs then -1 else 1) * r
h' : ∀ (i : Fin (n + 1)), w i * dist (s.points i) (s.altitudeFoot i) = (if i ∈ signs then -1 else 1) * r
h'' : ∀ (i : Fin (n + 1)), w i = r * s.excenterWeightsUnnorm signs i
⊢ w = s.excenterWeights signs

Tactic:
h'',

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
signs : Finset (Fin (n + 1))
r : ℝ
w : Fin (n + 1) → ℝ
hp : (Finset.affineCombination ℝ Finset.univ s.points) w ∈ affineSpan ℝ (Set.range s.points)
h :
  ∀ (i : Fin (n + 1)),
    (s.signedInfDist i) ((Finset.affineCombination ℝ Finset.univ s.points) w) = (if i ∈ signs then -1 else 1) * r
h' : ∀ (i : Fin (n + 1)), w i * dist (s.points i) (s.altitudeFoot i) = (if i ∈ signs then -1 else 1) * r
h'' : ∀ (i : Fin (n + 1)), w i = r * s.excenterWeightsUnnorm signs i
h1 : ∑ x, r * s.excenterWeightsUnnorm signs x = 1
⊢ w = s.excenterWeights signs
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
signs : Finset (Fin (n + 1))
r : ℝ
w : Fin (n + 1) → ℝ
hp : (Finset.affineCombination ℝ Finset.univ s.points) w ∈ affineSpan ℝ (Set.range s.points)
h :
  ∀ (i : Fin (n + 1)),
    (s.signedInfDist i) ((Finset.affineCombination ℝ Finset.univ s.points) w) = (if i ∈ signs then -1 else 1) * r
h' : ∀ (i : Fin (n + 1)), w i * dist (s.points i) (s.altitudeFoot i) = (if i ∈ signs then -1 else 1) * r
h'' : ∀ (i : Fin (n + 1)), w i = r * s.excenterWeightsUnnorm signs i
h1 : r * ∑ i, s.excenterWeightsUnnorm signs i = 1
j : Fin (n + 1)
⊢ w j = s.excenterWeights signs j

Tactic:
h'',

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
signs : Finset (Fin (n + 1))
r : ℝ
w : Fin (n + 1) → ℝ
hp : (Finset.affineCombination ℝ Finset.univ s.points) w ∈ affineSpan ℝ (Set.range s.points)
h :
  ∀ (i : Fin (n + 1)),
    (s.signedInfDist i) ((Finset.affineCombination ℝ Finset.univ s.points) w) = (if i ∈ signs then -1 else 1) * r
h' : ∀ (i : Fin (n + 1)), w i * dist (s.points i) (s.altitudeFoot i) = (if i ∈ signs then -1 else 1) * r
h'' : ∀ (i : Fin (n + 1)), w i = r * s.excenterWeightsUnnorm signs i
h1 : r * ∑ i, s.excenterWeightsUnnorm signs i = 1
j : Fin (n + 1)
⊢ r * s.excenterWeightsUnnorm signs j = s.excenterWeights signs j
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
n : ℕ
inst✝¹ : NeZero n
s : Simplex ℝ P n
inst✝ : n.AtLeastTwo
signs : Finset (Fin (n + 1))
h : s.ExcenterExists signs
i j : Fin (n + 1)
he : Pi.single j 1 = s.touchpointWeights signs i
this : 1 < n
k : Fin (n + 1)
hki : k ≠ i
hkj : k ≠ j
he' : SignType.sign (Pi.single j 1 k) = SignType.sign (s.touchpointWeights signs i k)
⊢ False

Tactic:
rw [Pi.single_eq_of_ne hkj, sign_zero, eq_comm, h.sign_touchpointWeights hki.symm,
    sign_eq_zero_iff, excenterWeights] at he'

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
n : ℕ
inst✝¹ : NeZero n
s : Simplex ℝ P n
inst✝ : n.AtLeastTwo
signs : Finset (Fin (n + 1))
h : s.ExcenterExists signs
i j : Fin (n + 1)
he : Pi.single j 1 = s.touchpointWeights signs i
this : 1 < n
k : Fin (n + 1)
hki : k ≠ i
hkj : k ≠ j
he' : ((∑ i, s.excenterWeightsUnnorm signs i)⁻¹ • s.excenterWeightsUnnorm signs) k = 0
⊢ False
Module: Mathlib.Topology.MetricSpace.Similarity

Goal state before:
pp: P₁ : Type u_3
P₂ : Type u_4
inst✝¹ : PseudoEMetricSpace P₁
inst✝ : PseudoEMetricSpace P₂
a b c : P₁
a' b' c' : P₂
h : ![a, b, c] ∼ ![a', b', c']
⊢ ![b, a, c] ∼ ![b', a', c']

Tactic:
have hl : ![b, a, c] = ![a, b, c] ∘ Equiv.swap 0 1 := by
    ext i
    fin_cases i <;> simp [Equiv.swap_apply_of_ne_of_ne]

Goal state after:
P₁ : Type u_3
P₂ : Type u_4
inst✝¹ : PseudoEMetricSpace P₁
inst✝ : PseudoEMetricSpace P₂
a b c : P₁
a' b' c' : P₂
h : ![a, b, c] ∼ ![a', b', c']
hl : ![b, a, c] = ![a, b, c] ∘ ⇑(Equiv.swap 0 1)
⊢ ![b, a, c] ∼ ![b', a', c']
Module: Mathlib.Geometry.Euclidean.NinePointCircle

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Triangle ℝ P
i : Fin 3
⊢ ((↑2 - 1) / ↑2) • (s.points i -ᵥ Simplex.mongePoint s) = s.points i -ᵥ midpoint ℝ (Simplex.mongePoint s) (s.points i)

Tactic:
vsub_midpoint

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Triangle ℝ P
i : Fin 3
⊢ ((↑2 - 1) / ↑2) • (s.points i -ᵥ Simplex.mongePoint s) =
    ⅟2 • (s.points i -ᵥ Simplex.mongePoint s) + ⅟2 • (s.points i -ᵥ s.points i)
Module: Mathlib.Geometry.Euclidean.Similarity

Goal state before:
pp: V₁ : Type u_2
V₂ : Type u_3
P₁ : Type u_4
P₂ : Type u_5
inst✝⁷ : NormedAddCommGroup V₁
inst✝⁶ : NormedAddCommGroup V₂
inst✝⁵ : InnerProductSpace ℝ V₁
inst✝⁴ : InnerProductSpace ℝ V₂
inst✝³ : MetricSpace P₁
inst✝² : MetricSpace P₂
inst✝¹ : NormedAddTorsor V₁ P₁
inst✝ : NormedAddTorsor V₂ P₂
a b c : P₁
a' b' c' : P₂
h_not_col : ¬Collinear ℝ {a, b, c}
h₁ : ∠ a b c = ∠ a' b' c'
h₂ : ∠ b c a = ∠ b' c' a'
hne_pi_div_two : ∠ a b c ≠ Real.pi / 2 ∨ ∠ b c a ≠ Real.pi / 2
not_all_eq : a' ≠ b' ∨ b' ≠ c' ∨ a' ≠ c'
h_not_col' : ¬Collinear ℝ {a', b', c'}
h_pos1 : 0 < dist a b
h_pos1' : 0 < dist a' b'
h_pos2 : 0 < dist b c
h_pos2' : 0 < dist b' c'
h₃ : ∠ c a b = ∠ c' a' b'
h_sin_ne1 : Real.sin (∠ b c a) ≠ 0
h_sin_ne2 : Real.sin (∠ c a b) ≠ 0
h_sin1 : dist a b * dist b' c' = dist b c * dist a' b'
h_sin1' : Real.sin (∠ c a b) = Real.sin (∠ b c a) * dist b' c' / dist a' b'
h_sin2 : Real.sin (∠ a b c) = Real.sin (∠ c a b) * dist c a / dist b c
h_sin2' : Real.sin (∠ a' b' c') = Real.sin (∠ c' a' b') * dist c' a' / dist b' c'
⊢ ![a, b, c] ∼ ![a', b', c']

Tactic:
← h₁,

Goal state after:
V₁ : Type u_2
V₂ : Type u_3
P₁ : Type u_4
P₂ : Type u_5
inst✝⁷ : NormedAddCommGroup V₁
inst✝⁶ : NormedAddCommGroup V₂
inst✝⁵ : InnerProductSpace ℝ V₁
inst✝⁴ : InnerProductSpace ℝ V₂
inst✝³ : MetricSpace P₁
inst✝² : MetricSpace P₂
inst✝¹ : NormedAddTorsor V₁ P₁
inst✝ : NormedAddTorsor V₂ P₂
a b c : P₁
a' b' c' : P₂
h_not_col : ¬Collinear ℝ {a, b, c}
h₁ : ∠ a b c = ∠ a' b' c'
h₂ : ∠ b c a = ∠ b' c' a'
hne_pi_div_two : ∠ a b c ≠ Real.pi / 2 ∨ ∠ b c a ≠ Real.pi / 2
not_all_eq : a' ≠ b' ∨ b' ≠ c' ∨ a' ≠ c'
h_not_col' : ¬Collinear ℝ {a', b', c'}
h_pos1 : 0 < dist a b
h_pos1' : 0 < dist a' b'
h_pos2 : 0 < dist b c
h_pos2' : 0 < dist b' c'
h₃ : ∠ c a b = ∠ c' a' b'
h_sin_ne1 : Real.sin (∠ b c a) ≠ 0
h_sin_ne2 : Real.sin (∠ c a b) ≠ 0
h_sin1 : dist a b * dist b' c' = dist b c * dist a' b'
h_sin1' : Real.sin (∠ c a b) = Real.sin (∠ b c a) * dist b' c' / dist a' b'
h_sin2 : Real.sin (∠ a b c) = Real.sin (∠ c a b) * dist c a / dist b c
h_sin2' : Real.sin (∠ a b c) = Real.sin (∠ c' a' b') * dist c' a' / dist b' c'
⊢ ![a, b, c] ∼ ![a', b', c']
Module: Mathlib.Geometry.Euclidean.Sphere.Power

Goal state before:
pp: V : Type u_1
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
P : Type u_2
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
p₁ p₂ p₃ p₄ p : P
h : dist p₁ p * dist p₂ p = dist p₃ p * dist p₄ p
hp₁p₂ : ∠ p₁ p p₂ = π
hp₃p₄ : ∠ p₃ p p₄ = π
hn : ¬Collinear ℝ {p₁, p, p₃}
hp₁p₂_sbtw : Sbtw ℝ p₁ p p₂
hp₃p₄_sbtw : Sbtw ℝ p₃ p p₄
hindep : AffineIndependent ℝ ![p₁, p, p₃]
t : Affine.Triangle ℝ P := { points := ![p₁, p, p₃], independent := hindep }
ht : t = { points := ![p₁, p, p₃], independent := hindep }
S : AffineSubspace ℝ P := affineSpan ℝ (Set.range t.points)
hS : S = affineSpan ℝ (Set.range t.points)
hp₂ : p₂ ∈ S
hp₄ : p₄ ∈ S
s_isom : ↥S →ᵃⁱ[ℝ] P := S.subtypeₐᵢ
p₁' : ↥S := ⟨p₁, ⋯⟩
⊢ Cospherical {p₁, p₂, p₃, p₄}

Tactic:
let p' : S := ⟨p, mem_affineSpan ℝ (s := Set.range t.points) (by aesop)⟩

Goal state after:
V : Type u_1
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
P : Type u_2
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
p₁ p₂ p₃ p₄ p : P
h : dist p₁ p * dist p₂ p = dist p₃ p * dist p₄ p
hp₁p₂ : ∠ p₁ p p₂ = π
hp₃p₄ : ∠ p₃ p p₄ = π
hn : ¬Collinear ℝ {p₁, p, p₃}
hp₁p₂_sbtw : Sbtw ℝ p₁ p p₂
hp₃p₄_sbtw : Sbtw ℝ p₃ p p₄
hindep : AffineIndependent ℝ ![p₁, p, p₃]
t : Affine.Triangle ℝ P := { points := ![p₁, p, p₃], independent := hindep }
ht : t = { points := ![p₁, p, p₃], independent := hindep }
S : AffineSubspace ℝ P := affineSpan ℝ (Set.range t.points)
hS : S = affineSpan ℝ (Set.range t.points)
hp₂ : p₂ ∈ S
hp₄ : p₄ ∈ S
s_isom : ↥S →ᵃⁱ[ℝ] P := S.subtypeₐᵢ
p₁' : ↥S := ⟨p₁, ⋯⟩
p' : ↥S := ⟨p, ⋯⟩
⊢ Cospherical {p₁, p₂, p₃, p₄}
Module: Mathlib.Geometry.Euclidean.MongePoint

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
t : Triangle ℝ P
i₁ i₂ : Fin 3
h : i₁ ≠ i₂
⊢ dist t.orthocenter ((reflection (affineSpan ℝ (t.points '' ↑{i₁, i₂}))) (circumcenter t)) = circumradius t

Tactic:
simp only [coe_insert, coe_singleton]

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
t : Triangle ℝ P
i₁ i₂ : Fin 3
h : i₁ ≠ i₂
⊢ dist t.orthocenter ((reflection (affineSpan ℝ (t.points '' {i₁, i₂}))) (circumcenter t)) = circumradius t
Module: Mathlib.Geometry.Euclidean.MongePoint

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
t : Triangle ℝ P
i₁ i₂ : Fin 3
h : i₁ ≠ i₂
⊢ dist (circumcenter t) ((reflection (affineSpan ℝ (t.points '' ↑{i₁, i₂}))) t.orthocenter) = circumradius t

Tactic:
simp only [coe_insert, coe_singleton]

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
t : Triangle ℝ P
i₁ i₂ : Fin 3
h : i₁ ≠ i₂
⊢ dist (circumcenter t) ((reflection (affineSpan ℝ (t.points '' {i₁, i₂}))) t.orthocenter) = circumradius t
Module: Mathlib.Geometry.Group.Growth.QuotientInter

Goal state before:
pp: G : Type u_1
inst✝³ : Group G
inst✝² : DecidableEq G
H : Subgroup G
inst✝¹ : DecidablePred fun x ↦ x ∈ H
inst✝ : H.Normal
A : Finset G
m n : ℕ
π : G →* G ⧸ H := QuotientGroup.mk' H
φ : G ⧸ H → G := invFunOn (⇑π) (↑A ^ m)
hφ : Set.InjOn φ (⇑π '' ↑A ^ m)
a : G ⧸ H
ha : a ∈ ⇑π '' ↑A ^ m
⊢ φ a ∈ A ^ m

Tactic:
have := invFunOn_mem (by simpa using ha)

Goal state after:
G : Type u_1
inst✝³ : Group G
inst✝² : DecidableEq G
H : Subgroup G
inst✝¹ : DecidablePred fun x ↦ x ∈ H
inst✝ : H.Normal
A : Finset G
m n : ℕ
π : G →* G ⧸ H := QuotientGroup.mk' H
φ : G ⧸ H → G := invFunOn (⇑π) (↑A ^ m)
hφ : Set.InjOn φ (⇑π '' ↑A ^ m)
a : G ⧸ H
ha : a ∈ ⇑π '' ↑A ^ m
this : invFunOn (⇑π) (↑A ^ m) a ∈ ↑A ^ m
⊢ φ a ∈ A ^ m
Module: Mathlib.Geometry.Manifold.DerivationBundle

Goal state before:
pp: 𝕜 : Type u_1
inst✝¹⁰ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝⁹ : NormedAddCommGroup E
inst✝⁸ : NormedSpace 𝕜 E
H : Type u_3
inst✝⁷ : TopologicalSpace H
I : ModelWithCorners 𝕜 E H
M : Type u_4
inst✝⁶ : TopologicalSpace M
inst✝⁵ : ChartedSpace H M
n : ℕ∞ω
X : Derivation 𝕜 C^∞⟮I, M; 𝓘(𝕜, 𝕜), 𝕜⟯ C^∞⟮I, M; 𝓘(𝕜, 𝕜), 𝕜⟯
f✝ : C^∞⟮I, M; 𝓘(𝕜, 𝕜), 𝕜⟯
E' : Type u_5
inst✝⁴ : NormedAddCommGroup E'
inst✝³ : NormedSpace 𝕜 E'
H' : Type u_6
inst✝² : TopologicalSpace H'
I' : ModelWithCorners 𝕜 E' H'
M' : Type u_7
inst✝¹ : TopologicalSpace M'
inst✝ : ChartedSpace H' M'
f : C^∞⟮I, M; I', M'⟯
x : M
y : M'
h : f x = y
v : PointDerivation I x
k : 𝕜
g : C^∞⟮I', M'; 𝕜⟯⟨y⟩
⊢ v (ContMDiffMap.comp (k • g) f) = (RingHom.id 𝕜) k • v (ContMDiffMap.comp g f)

Tactic:
dsimp; rw [ContMDiffMap.smul_comp, Derivation.map_smul, smul_eq_mul]

Goal state after:
Module: Mathlib.Geometry.Manifold.IsManifold.InteriorBoundary

Goal state before:
pp: 𝕜 : Type u_1
inst✝⁵ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace 𝕜 E
H : Type u_3
inst✝² : TopologicalSpace H
I : ModelWithCorners 𝕜 E H
M : Type u_4
inst✝¹ : TopologicalSpace M
inst✝ : ChartedSpace H M
x : M
⊢ I.IsInteriorPoint x ∨ I.IsBoundaryPoint x

Tactic:
rw [IsInteriorPoint, or_iff_not_imp_left, I.isBoundaryPoint_iff, ← closure_sdiff_interior,
    I.isClosed_range.closure_eq, mem_sdiff]
  exact fun h ↦ ⟨mem_range_self _, h⟩

Goal state after: