mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Topology.Algebra.Algebra

Goal state before:
pp: case mk
R : Type u_1
inst✝⁶ : CommSemiring R
A : Type u_2
inst✝⁵ : Semiring A
inst✝⁴ : TopologicalSpace A
B : Type u_3
inst✝³ : Semiring B
inst✝² : TopologicalSpace B
inst✝¹ : Algebra R A
inst✝ : Algebra R B
g : A →A[R] B
toAlgHom✝ : A →ₐ[R] B
cont✝ : Continuous[inst✝⁴, inst✝²] (↑↑toAlgHom✝.toRingHom).toFun
h : (fun f ↦ ⇑f.toAlgHom) { toAlgHom := toAlgHom✝, cont := cont✝ } = (fun f ↦ ⇑f.toAlgHom) g
⊢ { toAlgHom := toAlgHom✝, cont := cont✝ } = g

Tactic:
cases g

Goal state after:
case mk.mk
R : Type u_1
inst✝⁶ : CommSemiring R
A : Type u_2
inst✝⁵ : Semiring A
inst✝⁴ : TopologicalSpace A
B : Type u_3
inst✝³ : Semiring B
inst✝² : TopologicalSpace B
inst✝¹ : Algebra R A
inst✝ : Algebra R B
toAlgHom✝¹ : A →ₐ[R] B
cont✝¹ : Continuous[inst✝⁴, inst✝²] (↑↑toAlgHom✝¹.toRingHom).toFun
toAlgHom✝ : A →ₐ[R] B
cont✝ : Continuous[inst✝⁴, inst✝²] (↑↑toAlgHom✝.toRingHom).toFun
h :
  (fun f ↦ ⇑f.toAlgHom) { toAlgHom := toAlgHom✝¹, cont := cont✝¹ } =
    (fun f ↦ ⇑f.toAlgHom) { toAlgHom := toAlgHom✝, cont := cont✝ }
⊢ { toAlgHom := toAlgHom✝¹, cont := cont✝¹ } = { toAlgHom := toAlgHom✝, cont := cont✝ }
Module: Mathlib.Topology.Algebra.Algebra

Goal state before:
pp: case mk
R : Type u_1
inst✝⁶ : CommSemiring R
A : Type u_2
inst✝⁵ : Semiring A
inst✝⁴ : TopologicalSpace A
B : Type u_3
inst✝³ : Semiring B
inst✝² : TopologicalSpace B
inst✝¹ : Algebra R A
inst✝ : Algebra R B
g : A →A[R] B
toAlgHom✝ : A →ₐ[R] B
cont✝ : Continuous[inst✝⁴, inst✝²] (↑↑toAlgHom✝.toRingHom).toFun
⊢ ↑{ toAlgHom := toAlgHom✝, cont := cont✝ } = ↑g ↔ { toAlgHom := toAlgHom✝, cont := cont✝ } = g

Tactic:
cases g

Goal state after:
case mk.mk
R : Type u_1
inst✝⁶ : CommSemiring R
A : Type u_2
inst✝⁵ : Semiring A
inst✝⁴ : TopologicalSpace A
B : Type u_3
inst✝³ : Semiring B
inst✝² : TopologicalSpace B
inst✝¹ : Algebra R A
inst✝ : Algebra R B
toAlgHom✝¹ : A →ₐ[R] B
cont✝¹ : Continuous[inst✝⁴, inst✝²] (↑↑toAlgHom✝¹.toRingHom).toFun
toAlgHom✝ : A →ₐ[R] B
cont✝ : Continuous[inst✝⁴, inst✝²] (↑↑toAlgHom✝.toRingHom).toFun
⊢ ↑{ toAlgHom := toAlgHom✝¹, cont := cont✝¹ } = ↑{ toAlgHom := toAlgHom✝, cont := cont✝ } ↔
    { toAlgHom := toAlgHom✝¹, cont := cont✝¹ } = { toAlgHom := toAlgHom✝, cont := cont✝ }
Module: Mathlib.Data.EReal.Inv

Goal state before:
pp: ⊢ 0⁻¹ = 0

Tactic:
change (0 : ℝ)⁻¹ = (0 : EReal)
  rw [GroupWithZero.inv_zero, coe_zero]

Goal state after:
Module: Mathlib.Data.EReal.Inv

Goal state before:
pp: case coe_coe
x y : ℝ
⊢ (↑x * ↑y)⁻¹ = (↑x)⁻¹ * (↑y)⁻¹

Tactic:
| coe_coe x y =>

Goal state after:
Module: Mathlib.Data.EReal.Inv

Goal state before:
pp: a b : EReal
⊢ (a * b)⁻¹ = a⁻¹ * b⁻¹

Tactic:
by
  induction a, b using EReal.induction₂_symm with
  | top_top | top_zero | top_bot | zero_bot | bot_bot => simp
  | @symm a b h => rw [mul_comm b a, mul_comm b⁻¹ a⁻¹]; exact h
  | top_pos x x_pos => rw [top_mul_of_pos (EReal.coe_pos.2 x_pos), inv_top, zero_mul]
  | top_neg x x_neg => rw [top_mul_of_neg (EReal.coe_neg'.2 x_neg), inv_bot, inv_top, zero_mul]
  | pos_bot x x_pos => rw [mul_bot_of_pos (EReal.coe_pos.2 x_pos), inv_bot, mul_zero]
  | coe_coe x y => rw [← coe_mul, ← coe_inv, _root_.mul_inv, coe_mul, coe_inv, coe_inv]
  | neg_bot x x_neg => rw [mul_bot_of_neg (EReal.coe_neg'.2 x_neg), inv_top, inv_bot, mul_zero]

Goal state after:
Module: Mathlib.Topology.Semicontinuity.Defs

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝¹ : TopologicalSpace α
inst✝ : TopologicalSpace β
f : α → Set β
x : α
⊢ UpperHemicontinuousAt f x ↔
    ∀ (t : Set β), IsClosed[inst✝] t → (∃ᶠ (x' : α) in 𝓝 x, (f x' ∩ t).Nonempty) → (f x ∩ t).Nonempty

Tactic:
by
  rw [← upperHemicontinuousWithinAt_univ_iff, upperHemicontinuousWithinAt_iff_frequently]
  simp

Goal state after:
Module: Mathlib.Data.EReal.Inv

Goal state before:
pp: a b : EReal
h₁ : b ≠ ⊥
h₂ : b ≠ ⊤
h₃ : b ≠ 0
⊢ a / b * b = a

Tactic:
div_mul_cancel h₁ h₂ h₃

Goal state after:
a b : EReal
h₁ : b ≠ ⊥
h₂ : b ≠ ⊤
h₃ : b ≠ 0
⊢ a = a
Module: Mathlib.Data.EReal.Inv

Goal state before:
pp: a b c : EReal
h₁ : c ≠ ⊥
h₂ : c ≠ ⊤
h₃ : c ≠ 0
⊢ a / b / c * c = a / b

Tactic:
div_mul_cancel h₁ h₂ h₃

Goal state after:
a b c : EReal
h₁ : c ≠ ⊥
h₂ : c ≠ ⊤
h₃ : c ≠ 0
⊢ a / b = a / b
Module: Mathlib.Topology.Semicontinuity.Basic

Goal state before:
pp: case neg
α : Type u_1
β : Type u_2
inst✝² : TopologicalSpace α
s : Set α
y : β
inst✝¹ : Zero β
inst✝ : Preorder β
hs : IsClosed[inst✝²] s
hy : y ≤ 0
x : α
z : β
h : x ∉ s
hz : z < 0
⊢ ∀ᶠ (x' : α) in 𝓝 x, (fun x1 x2 ↦ s.indicator (fun _x ↦ y) x1 > x2) x' z

Tactic:
filter_upwards [hs.isOpen_compl.mem_nhds h]
    simp +contextual [hz]

Goal state after:
Module: Mathlib.MeasureTheory.OuterMeasure.OfFunction

Goal state before:
pp: α : Type u_1
m : Set α → ℝ≥0∞
m_empty : m ∅ = 0
μ : Set α → ℝ≥0∞ := fun s ↦ ⨅ f, ⨅ (_ : s ⊆ ⋃ i, f i), ∑' (i : ℕ), m (f i)
s : ℕ → Set α
x✝ : Pairwise (Disjoint on s)
ε : ℝ≥0
hε : 0 < ε
hb : ∑' (i : ℕ), μ (s i) < ∞
ε' : ℕ → ℝ≥0
hε' : ∀ (i : ℕ), 0 < ε' i
hl : ∑' (i : ℕ), ↑(ε' i) < ↑ε
⊢ μ (⋃ i, s i) ≤ ∑' (i : ℕ), μ (s i) + ∑' (i : ℕ), ↑(ε' i)

Tactic:
rw [← ENNReal.tsum_add]

Goal state after:
α : Type u_1
m : Set α → ℝ≥0∞
m_empty : m ∅ = 0
μ : Set α → ℝ≥0∞ := fun s ↦ ⨅ f, ⨅ (_ : s ⊆ ⋃ i, f i), ∑' (i : ℕ), m (f i)
s : ℕ → Set α
x✝ : Pairwise (Disjoint on s)
ε : ℝ≥0
hε : 0 < ε
hb : ∑' (i : ℕ), μ (s i) < ∞
ε' : ℕ → ℝ≥0
hε' : ∀ (i : ℕ), 0 < ε' i
hl : ∑' (i : ℕ), ↑(ε' i) < ↑ε
⊢ μ (⋃ i, s i) ≤ ∑' (a : ℕ), (μ (s a) + ↑(ε' a))
Module: Mathlib.Topology.Semicontinuity.Basic

Goal state before:
pp: α : Type u_1
inst✝⁵ : TopologicalSpace α
s : Set α
x : α
γ : Type u_5
inst✝⁴ : AddCommMonoid γ
inst✝³ : LinearOrder γ
inst✝² : IsOrderedAddMonoid γ
inst✝¹ : TopologicalSpace γ
inst✝ : OrderTopology γ
f g : α → γ
hf : LowerSemicontinuousWithinAt f s x
hg : LowerSemicontinuousWithinAt g s x
hcont : ContinuousAt (fun p ↦ p.1 + p.2) (f x, g x)
y : γ
hy : (fun z ↦ f z + g z) x > y
u v : Set γ
u_open : IsOpen[inst✝¹] u
xu : f x ∈ u
v_open : IsOpen[inst✝¹] v
xv : g x ∈ v
h : u ×ˢ v ⊆ {p | y < p.1 + p.2}
hx₁ : ∃ l, l < f x
z₁ : γ
z₁lt : z₁ < f x
h₁ : Ioc z₁ (f x) ⊆ u
hx₂ : ∃ l, l < g x
z₂ : γ
z₂lt : z₂ < g x
h₂ : Ioc z₂ (g x) ⊆ v
z : α
⊢ f z > z₁ → g z > z₂ → f z + g z > y

Tactic:
h₁z

Goal state after:
α : Type u_1
inst✝⁵ : TopologicalSpace α
s : Set α
x : α
γ : Type u_5
inst✝⁴ : AddCommMonoid γ
inst✝³ : LinearOrder γ
inst✝² : IsOrderedAddMonoid γ
inst✝¹ : TopologicalSpace γ
inst✝ : OrderTopology γ
f g : α → γ
hf : LowerSemicontinuousWithinAt f s x
hg : LowerSemicontinuousWithinAt g s x
hcont : ContinuousAt (fun p ↦ p.1 + p.2) (f x, g x)
y : γ
hy : (fun z ↦ f z + g z) x > y
u v : Set γ
u_open : IsOpen[inst✝¹] u
xu : f x ∈ u
v_open : IsOpen[inst✝¹] v
xv : g x ∈ v
h : u ×ˢ v ⊆ {p | y < p.1 + p.2}
hx₁ : ∃ l, l < f x
z₁ : γ
z₁lt : z₁ < f x
h₁ : Ioc z₁ (f x) ⊆ u
hx₂ : ∃ l, l < g x
z₂ : γ
z₂lt : z₂ < g x
h₂ : Ioc z₂ (g x) ⊆ v
z : α
h₁z : f z > z₁
⊢ g z > z₂ → f z + g z > y
Module: Mathlib.Topology.Semicontinuity.Basic

Goal state before:
pp: α : Type u_1
inst✝⁵ : TopologicalSpace α
s : Set α
x : α
γ : Type u_5
inst✝⁴ : AddCommMonoid γ
inst✝³ : LinearOrder γ
inst✝² : IsOrderedAddMonoid γ
inst✝¹ : TopologicalSpace γ
inst✝ : OrderTopology γ
f g : α → γ
hf : LowerSemicontinuousWithinAt f s x
hg : LowerSemicontinuousWithinAt g s x
hcont : ContinuousAt (fun p ↦ p.1 + p.2) (f x, g x)
y : γ
hy : (fun z ↦ f z + g z) x > y
u v : Set γ
u_open : IsOpen[inst✝¹] u
xu : f x ∈ u
v_open : IsOpen[inst✝¹] v
xv : g x ∈ v
h : u ×ˢ v ⊆ {p | y < p.1 + p.2}
hx₁ : ∃ l, l < f x
z₁ : γ
z₁lt : z₁ < f x
h₁ : Ioc z₁ (f x) ⊆ u
hx₂ : ∀ (x_1 : γ), g x ≤ x_1
z : α
⊢ f z > z₁ → f z + g z > y

Tactic:
h₁z

Goal state after:
α : Type u_1
inst✝⁵ : TopologicalSpace α
s : Set α
x : α
γ : Type u_5
inst✝⁴ : AddCommMonoid γ
inst✝³ : LinearOrder γ
inst✝² : IsOrderedAddMonoid γ
inst✝¹ : TopologicalSpace γ
inst✝ : OrderTopology γ
f g : α → γ
hf : LowerSemicontinuousWithinAt f s x
hg : LowerSemicontinuousWithinAt g s x
hcont : ContinuousAt (fun p ↦ p.1 + p.2) (f x, g x)
y : γ
hy : (fun z ↦ f z + g z) x > y
u v : Set γ
u_open : IsOpen[inst✝¹] u
xu : f x ∈ u
v_open : IsOpen[inst✝¹] v
xv : g x ∈ v
h : u ×ˢ v ⊆ {p | y < p.1 + p.2}
hx₁ : ∃ l, l < f x
z₁ : γ
z₁lt : z₁ < f x
h₁ : Ioc z₁ (f x) ⊆ u
hx₂ : ∀ (x_1 : γ), g x ≤ x_1
z : α
h₁z : f z > z₁
⊢ f z + g z > y
Module: Mathlib.MeasureTheory.OuterMeasure.Induced

Goal state before:
pp: case intro
α : Type u_1
P : Set α → Prop
m : (s : Set α) → P s → ℝ≥0∞
P0 : P ∅
m0 : m ∅ P0 = 0
PU : ∀ ⦃f : ℕ → Set α⦄, (∀ (i : ℕ), P (f i)) → P (⋃ i, f i)
mU : ∀ ⦃f : ℕ → Set α⦄ (hm : ∀ (i : ℕ), P (f i)), Pairwise (Disjoint on f) → m (⋃ i, f i) ⋯ = ∑' (i : ℕ), m (f i) ⋯
β : Type u_2
inst✝ : Countable β
f : β → Set α
hd : Pairwise (Disjoint on f)
hm : ∀ (i : β), P (f i)
val✝ : Encodable β
⊢ extend m (⋃ i, f i) = ∑' (i : β), extend m (f i)

Tactic:
← Encodable.iUnion_decode₂,

Goal state after:
case intro
α : Type u_1
P : Set α → Prop
m : (s : Set α) → P s → ℝ≥0∞
P0 : P ∅
m0 : m ∅ P0 = 0
PU : ∀ ⦃f : ℕ → Set α⦄, (∀ (i : ℕ), P (f i)) → P (⋃ i, f i)
mU : ∀ ⦃f : ℕ → Set α⦄ (hm : ∀ (i : ℕ), P (f i)), Pairwise (Disjoint on f) → m (⋃ i, f i) ⋯ = ∑' (i : ℕ), m (f i) ⋯
β : Type u_2
inst✝ : Countable β
f : β → Set α
hd : Pairwise (Disjoint on f)
hm : ∀ (i : β), P (f i)
val✝ : Encodable β
⊢ extend m (⋃ i, ⋃ b ∈ Encodable.decode₂ β i, f b) = ∑' (i : β), extend m (f i)
Module: Mathlib.MeasureTheory.OuterMeasure.Caratheodory

Goal state before:
pp: case refine_3
α : Type u_1
m : Set α → ℝ≥0∞
s : Set α
h₀ : m ∅ = 0
hs : ∀ (t : Set α), m (t ∩ s) + m (t \ s) ≤ m t
t : Set α
f : ℕ → Set α
hf : t ⊆ ⋃ i, f i
⊢ ∑' (i : ℕ), m ((fun i ↦ f i ∩ s) i) + ∑' (i : ℕ), m ((fun i ↦ f i \ s) i) ≤ ∑' (i : ℕ), m (f i)

Tactic:
rw [← ENNReal.tsum_add]

Goal state after:
case refine_3
α : Type u_1
m : Set α → ℝ≥0∞
s : Set α
h₀ : m ∅ = 0
hs : ∀ (t : Set α), m (t ∩ s) + m (t \ s) ≤ m t
t : Set α
f : ℕ → Set α
hf : t ⊆ ⋃ i, f i
⊢ ∑' (a : ℕ), (m ((fun i ↦ f i ∩ s) a) + m ((fun i ↦ f i \ s) a)) ≤ ∑' (i : ℕ), m (f i)
Module: Mathlib.MeasureTheory.OuterMeasure.Induced

Goal state before:
pp: case a
α : Type u_1
P : Set α → Prop
m : (s : Set α) → P s → ℝ≥0∞
P0 : P ∅
m0 : m ∅ P0 = 0
PU : ∀ ⦃f : ℕ → Set α⦄, (∀ (i : ℕ), P (f i)) → P (⋃ i, f i)
msU : ∀ ⦃f : ℕ → Set α⦄ (hm : ∀ (i : ℕ), P (f i)), m (⋃ i, f i) ⋯ ≤ ∑' (i : ℕ), m (f i) ⋯
m_mono : ∀ ⦃s₁ s₂ : Set α⦄ (hs₁ : P s₁) (hs₂ : P s₂), s₁ ⊆ s₂ → m s₁ hs₁ ≤ m s₂ hs₂
s : Set α
⊢ (inducedOuterMeasure m P0 m0) s ≤ ⨅ t, ⨅ (ht : P t), ⨅ (_ : s ⊆ t), m t ht

Tactic:
simp only [le_iInf_iff]

Goal state after:
case a
α : Type u_1
P : Set α → Prop
m : (s : Set α) → P s → ℝ≥0∞
P0 : P ∅
m0 : m ∅ P0 = 0
PU : ∀ ⦃f : ℕ → Set α⦄, (∀ (i : ℕ), P (f i)) → P (⋃ i, f i)
msU : ∀ ⦃f : ℕ → Set α⦄ (hm : ∀ (i : ℕ), P (f i)), m (⋃ i, f i) ⋯ ≤ ∑' (i : ℕ), m (f i) ⋯
m_mono : ∀ ⦃s₁ s₂ : Set α⦄ (hs₁ : P s₁) (hs₂ : P s₂), s₁ ⊆ s₂ → m s₁ hs₁ ≤ m s₂ hs₂
s : Set α
⊢ ∀ (i : Set α) (i_1 : P i), s ⊆ i → (inducedOuterMeasure m P0 m0) s ≤ m i i_1
Module: Mathlib.MeasureTheory.OuterMeasure.AE

Goal state before:
pp: α : Type u_1
F : Type u_3
inst✝² : FunLike F (Set α) ℝ≥0∞
inst✝¹ : OuterMeasureClass F α
μ : F
inst✝ : Countable α
p : α → Prop
⊢ (∀ᵐ (x : α) ∂μ, p x) ↔ ∀ (x : α), μ {x} ≠ 0 → p x

Tactic:
rw [ae_iff, measure_null_iff_singleton]

Goal state after:
α : Type u_1
F : Type u_3
inst✝² : FunLike F (Set α) ℝ≥0∞
inst✝¹ : OuterMeasureClass F α
μ : F
inst✝ : Countable α
p : α → Prop
⊢ (∀ x ∈ {a | ¬p a}, μ {x} = 0) ↔ ∀ (x : α), μ {x} ≠ 0 → p x

α : Type u_1
F : Type u_3
inst✝² : FunLike F (Set α) ℝ≥0∞
inst✝¹ : OuterMeasureClass F α
μ : F
inst✝ : Countable α
p : α → Prop
⊢ {a | ¬p a}.Countable
Module: Mathlib.MeasureTheory.PiSystem

Goal state before:
pp: case refine_2
α : Type u_3
ι : Type u_4
m : ι → MeasurableSpace α
S : Set ι
⊢ ⨆ i ∈ S, m i ≤ generateFrom (piiUnionInter (fun n ↦ {s | MeasurableSet s}) S)

Tactic:
· refine iSup₂_le fun i hi => ?_
    rw [← @generateFrom_measurableSet α (m i)]
    exact generateFrom_mono (mem_piiUnionInter_of_measurableSet m hi)

Goal state after:
Module: Mathlib.MeasureTheory.PiSystem

Goal state before:
pp: α : Type u_3
m : MeasurableSpace α
C : (s : Set α) → MeasurableSet s → Prop
s : Set (Set α)
h_eq : m = generateFrom s
h_inter : IsPiSystem s
empty : C ∅ ⋯
basic : ∀ (t : Set α) (ht : t ∈ s), C t ⋯
compl : ∀ (t : Set α) (htm : MeasurableSet t), C t htm → C tᶜ ⋯
iUnion :
  ∀ (f : ℕ → Set α),
    Pairwise (Disjoint on f) → ∀ (hfm : ∀ (i : ℕ), MeasurableSet (f i)), (∀ (i : ℕ), C (f i) ⋯) → C (⋃ i, f i) ⋯
⊢ ∀ (t : Set α) (ht : MeasurableSet t), C t ht

Tactic:
by
  have eq : MeasurableSet = DynkinSystem.GenerateHas s := by
    rw [h_eq, DynkinSystem.generateFrom_eq h_inter]
    rfl
  suffices ∀ t (ht : DynkinSystem.GenerateHas s t), C t (eq ▸ ht) from
    fun t ht ↦ this t (eq ▸ ht)
  intro t ht
  induction ht with
  | basic u hu => exact basic u hu
  | empty => exact empty
  | @compl u hu ihu => exact compl _ (eq ▸ hu) ihu
  | @iUnion f hfd hf ihf => exact iUnion f hfd (eq ▸ hf) ihf

Goal state after:
Module: Mathlib.MeasureTheory.Measure.MeasureSpaceDef

Goal state before:
pp: case right
α : Type u_1
m : MeasurableSpace α
μ : Measure α
δ : Type u_6
X : δ → Type u_7
mX : (a : δ) → MeasurableSpace (X a)
g : α → (a : δ) → X a
hg : AEMeasurable g μ
a : δ
⊢ (fun x ↦ g x a) =ᵐ[μ] fun x ↦ mk g hg x a

Tactic:
exact hg.ae_eq_mk.mono fun _ h ↦ congrFun h _

Goal state after:
Module: Mathlib.MeasureTheory.MeasurableSpace.EventuallyMeasurable

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
s✝ t : Set α
l : Filter α
inst✝ : CountableInterFilter l
s : ℕ → Set α
hs : ∀ (i : ℕ), ∃ t, MeasurableSet t ∧ s i =ᶠ[l] t
⊢ ∃ t, MeasurableSet t ∧ ⋃ i, s i =ᶠ[l] t

Tactic:
by
    choose t ht hts using hs
    exact ⟨⋃ i, t i, MeasurableSet.iUnion ht, .countable_iUnion hts⟩

Goal state after:
Module: Mathlib.MeasureTheory.OuterMeasure.Induced

Goal state before:
pp: α : Type u_1
inst✝ : MeasurableSpace α
m : (s : Set α) → MeasurableSet s → ℝ≥0∞
m0 : m ∅ ⋯ = 0
mU :
  ∀ ⦃f : ℕ → Set α⦄ (hm : ∀ (i : ℕ), MeasurableSet (f i)),
    Pairwise (Disjoint on f) → m (⋃ i, f i) ⋯ = ∑' (i : ℕ), m (f i) ⋯
s₁ s₂ : Set α
h₁ : MeasurableSet s₁
hs : s₁ ⊆ s₂
h₂ : MeasurableSet s₂
this : extend m s₂ = extend m s₁ + extend m (s₂ \ s₁)
⊢ extend m s₁ ≤ m s₂ h₂

Tactic:
← extend_eq m

Goal state after:
α : Type u_1
inst✝ : MeasurableSpace α
m : (s : Set α) → MeasurableSet s → ℝ≥0∞
m0 : m ∅ ⋯ = 0
mU :
  ∀ ⦃f : ℕ → Set α⦄ (hm : ∀ (i : ℕ), MeasurableSet (f i)),
    Pairwise (Disjoint on f) → m (⋃ i, f i) ⋯ = ∑' (i : ℕ), m (f i) ⋯
s₁ s₂ : Set α
h₁ : MeasurableSet s₁
hs : s₁ ⊆ s₂
h₂ : MeasurableSet s₂
this : extend m s₂ = extend m s₁ + extend m (s₂ \ s₁)
⊢ extend m s₁ ≤ extend m s₂
Module: Mathlib.MeasureTheory.OuterMeasure.Induced

Goal state before:
pp: α : Type u_1
inst✝ : MeasurableSpace α
m : (s : Set α) → MeasurableSet s → ℝ≥0∞
m0 : m ∅ ⋯ = 0
mU :
  ∀ ⦃f : ℕ → Set α⦄ (hm : ∀ (i : ℕ), MeasurableSet (f i)),
    Pairwise (Disjoint on f) → m (⋃ i, f i) ⋯ = ∑' (i : ℕ), m (f i) ⋯
f : ℕ → Set α
h : ∀ (i : ℕ), MeasurableSet (f i)
i : ℕ
⊢ extend m (disjointed f i) ≤ m (f i) ⋯

Tactic:
← extend_eq m

Goal state after:
α : Type u_1
inst✝ : MeasurableSpace α
m : (s : Set α) → MeasurableSet s → ℝ≥0∞
m0 : m ∅ ⋯ = 0
mU :
  ∀ ⦃f : ℕ → Set α⦄ (hm : ∀ (i : ℕ), MeasurableSet (f i)),
    Pairwise (Disjoint on f) → m (⋃ i, f i) ⋯ = ∑' (i : ℕ), m (f i) ⋯
f : ℕ → Set α
h : ∀ (i : ℕ), MeasurableSet (f i)
i : ℕ
⊢ extend m (disjointed f i) ≤ extend m (f i)
Module: Mathlib.MeasureTheory.MeasurableSpace.Embedding

Goal state before:
pp: α : Type u_1
β : Type u_2
mα : MeasurableSpace α
inst✝ : MeasurableSpace β
f : α → β
hf : MeasurableEmbedding f
s : Set α
hs : MeasurableSet s
⊢ MeasurableSet (rangeSplitting f ⁻¹' s)

Tactic:
rwa [preimage_rangeSplitting hf.injective,
    ← (subtype_coe hf.measurableSet_range).measurableSet_image, ← image_comp,
    coe_comp_rangeFactorization, hf.measurableSet_image]

Goal state after:
Module: Mathlib.MeasureTheory.MeasurableSpace.Embedding

Goal state before:
pp: α✝ : Type u_1
β✝ : Type u_2
γ✝ : Type u_3
δ : Type u_4
δ' : Type u_5
ι : Sort uι
s t u : Set α✝
inst✝⁶ : MeasurableSpace α✝
inst✝⁵ : MeasurableSpace β✝
inst✝⁴ : MeasurableSpace γ✝
π : δ' → Type u_6
π' : δ' → Type u_7
inst✝³ : (x : δ') → MeasurableSpace (π x)
inst✝² : (x : δ') → MeasurableSpace (π' x)
α : Type u_8
β : Type u_9
γ : Type u_10
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
⊢ Measurable ⇑(Equiv.arrowProdEquivProdArrow γ (fun i ↦ α) fun i ↦ β)

Tactic:
dsimp [Equiv.arrowProdEquivProdArrow]

Goal state after:
α✝ : Type u_1
β✝ : Type u_2
γ✝ : Type u_3
δ : Type u_4
δ' : Type u_5
ι : Sort uι
s t u : Set α✝
inst✝⁶ : MeasurableSpace α✝
inst✝⁵ : MeasurableSpace β✝
inst✝⁴ : MeasurableSpace γ✝
π : δ' → Type u_6
π' : δ' → Type u_7
inst✝³ : (x : δ') → MeasurableSpace (π x)
inst✝² : (x : δ') → MeasurableSpace (π' x)
α : Type u_8
β : Type u_9
γ : Type u_10
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
⊢ Measurable fun f ↦ (fun c ↦ (f c).1, fun c ↦ (f c).2)
Module: Mathlib.MeasureTheory.MeasurableSpace.Embedding

Goal state before:
pp: α✝ : Type u_1
β✝ : Type u_2
γ✝ : Type u_3
δ : Type u_4
δ' : Type u_5
ι : Sort uι
s t u : Set α✝
inst✝⁶ : MeasurableSpace α✝
inst✝⁵ : MeasurableSpace β✝
inst✝⁴ : MeasurableSpace γ✝
π : δ' → Type u_6
π' : δ' → Type u_7
inst✝³ : (x : δ') → MeasurableSpace (π x)
inst✝² : (x : δ') → MeasurableSpace (π' x)
α : Type u_8
β : Type u_9
γ : Type u_10
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
⊢ Measurable ⇑(Equiv.arrowProdEquivProdArrow γ (fun i ↦ α) fun i ↦ β).symm

Tactic:
dsimp [Equiv.arrowProdEquivProdArrow]

Goal state after:
α✝ : Type u_1
β✝ : Type u_2
γ✝ : Type u_3
δ : Type u_4
δ' : Type u_5
ι : Sort uι
s t u : Set α✝
inst✝⁶ : MeasurableSpace α✝
inst✝⁵ : MeasurableSpace β✝
inst✝⁴ : MeasurableSpace γ✝
π : δ' → Type u_6
π' : δ' → Type u_7
inst✝³ : (x : δ') → MeasurableSpace (π x)
inst✝² : (x : δ') → MeasurableSpace (π' x)
α : Type u_8
β : Type u_9
γ : Type u_10
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
⊢ Measurable fun p c ↦ (p.1 c, p.2 c)
Module: Mathlib.MeasureTheory.Measure.QuasiMeasurePreserving

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
μa : Measure α
μb : Measure β
μc : Measure γ
g : β → γ
f : α → β
hg : QuasiMeasurePreserving g μb μc
hf : QuasiMeasurePreserving f μa μb
⊢ map (g ∘ f) μa ≪ μc

Tactic:
rw [← map_map hg.1 hf.1]

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
μa : Measure α
μb : Measure β
μc : Measure γ
g : β → γ
f : α → β
hg : QuasiMeasurePreserving g μb μc
hf : QuasiMeasurePreserving f μa μb
⊢ map g (map f μa) ≪ μc
Module: Mathlib.MeasureTheory.Measure.QuasiMeasurePreserving

Goal state before:
pp: case inl
α : Type u_1
mα : MeasurableSpace α
μ : Measure α
s : Set α
e : α ≃ α
he : QuasiMeasurePreserving (⇑e) μ μ
he' : QuasiMeasurePreserving (⇑e.symm) μ μ
hs : ⇑e '' s =ᵐ[μ] s
k : ℕ
⊢ ⇑(e ^ ↑k).symm ⁻¹' s =ᵐ[μ] s

Tactic:
replace hs : (⇑e⁻¹) ⁻¹' s =ᵐ[μ] s := by rwa [Equiv.image_eq_preimage_symm] at hs

Goal state after:
case inl
α : Type u_1
mα : MeasurableSpace α
μ : Measure α
s : Set α
e : α ≃ α
he : QuasiMeasurePreserving (⇑e) μ μ
he' : QuasiMeasurePreserving (⇑e.symm) μ μ
k : ℕ
hs : ⇑e⁻¹ ⁻¹' s =ᵐ[μ] s
⊢ ⇑(e ^ ↑k).symm ⁻¹' s =ᵐ[μ] s
Module: Mathlib.MeasureTheory.Measure.Comap

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
f : α → β
g : β → γ
hf' : ∀ (s : Set α), MeasurableSet s → MeasurableSet (f '' s)
hg : Injective g
hg' : ∀ (s : Set β), MeasurableSet s → MeasurableSet (g '' s)
μ : Measure γ
⊢ comap f (comap g μ) = comap (g ∘ f) μ

Tactic:
by_cases hf : Injective f
  · ext s hs
    rw [comap_apply _ hf hf' _ hs, comap_apply _ hg hg' _ (hf' _ hs),
      comap_apply _ (hg.comp hf) (fun t ht ↦ image_comp g f _ ▸ hg' _ <| hf' _ ht) _ hs, image_comp]
  · rw [comap, dif_neg <| mt And.left hf, comap, dif_neg fun h ↦ hf h.1.of_comp]

Goal state after:
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: α : Type u_1
ι : Type u_5
m : MeasurableSpace α
μ : Measure α
s : Finset ι
f : ι → Set α
hd : (↑s).Pairwise (AEDisjoint μ on f)
hm : ∀ b ∈ s, NullMeasurableSet (f b) μ
⊢ μ (⋃ b ∈ s, f b) = ∑ p ∈ s, μ (f p)

Tactic:
by
  rw [← Finset.sum_attach, Finset.attach_eq_univ, ← tsum_fintype (L := .unconditional s)]
  exact measure_biUnion₀ s.countable_toSet hd hm

Goal state after:
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
s t : Set α
hμst : μ (s ∆ t) ≠ ∞
⊢ μ s = ∞ ↔ μ t = ∞

Tactic:
suffices h : ∀ u v, μ (u ∆ v) ≠ ∞ → μ u = ∞ → μ v = ∞
    from ⟨h s t hμst, h t s (symmDiff_comm s t ▸ hμst)⟩

Goal state after:
α : Type u_1
m : MeasurableSpace α
μ : Measure α
s t : Set α
hμst : μ (s ∆ t) ≠ ∞
⊢ ∀ (u v : Set α), μ (u ∆ v) ≠ ∞ → μ u = ∞ → μ v = ∞
Module: Mathlib.Topology.Order.AtTopBotIxx

Goal state before:
pp: case pos.mpr.refine_2
X : Type u_1
inst✝² : LinearOrder X
inst✝¹ : TopologicalSpace X
inst✝ : OrderTopology X
s : Set X
b : X
hsne : s.Nonempty
this : Nonempty ↑s
hsub : s ⊆ Iio b
h : ∀ a < b, (s ∩ Ioo a b).Nonempty
a : X
has : a ∈ s
⊢ ∃ i < b, Subtype.val ⁻¹' Ioo i b ⊆ Ici ⟨a, has⟩

Tactic:
use a, hsub has

Goal state after:
case right
X : Type u_1
inst✝² : LinearOrder X
inst✝¹ : TopologicalSpace X
inst✝ : OrderTopology X
s : Set X
b : X
hsne : s.Nonempty
this : Nonempty ↑s
hsub : s ⊆ Iio b
h : ∀ a < b, (s ∩ Ioo a b).Nonempty
a : X
has : a ∈ s
⊢ Subtype.val ⁻¹' Ioo a b ⊆ Ici ⟨a, has⟩
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: α : Type u_1
m : MeasurableSpace α
μ : Measure α
t : ℕ → Set α
hd : Directed (fun x1 x2 ↦ x1 ⊆ x2) t
T : ℕ → Set α := fun n ↦ toMeasurable μ (t n)
Td : ℕ → Set α := disjointed T
hm : ∀ (n : ℕ), MeasurableSet (Td n)
⊢ μ (⋃ n, t n) = μ (⋃ n, Td n)

Tactic:
by rw [iUnion_disjointed, measure_iUnion_toMeasurable]

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Typeclasses.SFinite

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
inst✝ : SigmaFinite ν
⊢ (sum fun n ↦ μ.restrict (disjointed (spanningSets ν) n)) = μ

Tactic:
← restrict_iUnion (disjoint_disjointed _)
      (MeasurableSet.disjointed (measurableSet_spanningSets _)),

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ ν : Measure α
inst✝ : SigmaFinite ν
⊢ μ.restrict (⋃ i, disjointed (spanningSets ν) i) = μ
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
m0 : MeasurableSpace α
μ : Measure α
s t : Set α
ht : MeasurableSet t
⊢ (μ.restrict s) t = 0 ↔ μ (t ∩ s) = 0

Tactic:
rw [restrict_apply ht]

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Restrict

Goal state before:
pp: α : Type u_2
m0 : MeasurableSpace α
μ : Measure α
t s : Set α
ht : NullMeasurableSet t μ
u : Set α
hu : MeasurableSet u
⊢ μ (u ∩ s ∩ t) + μ (u ∩ s ∩ tᶜ) = μ (u ∩ s)

Tactic:
exact measure_inter_add_sdiff₀ (u ∩ s) ht

Goal state after:
Module: Mathlib.MeasureTheory.Measure.MeasureSpace

Goal state before:
pp: α : Type u_1
ms : MeasurableSpace α
μ : OuterMeasure α
h : ms ≤ μ.caratheodory
hμ : μ.toMeasure h = 0
⊢ μ = 0

Tactic:
by ext s; exact le_bot_iff.1 <| (le_toMeasure_apply _ _ _).trans_eq congr($hμ s)

Goal state after:
Module: Mathlib.MeasureTheory.Measure.Trim

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
⊢ SigmaFinite (μ.trim ⋯) ↔ IsFiniteMeasure μ

Tactic:
sigmaFinite_bot_iff

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
⊢ IsFiniteMeasure (μ.trim ⋯) ↔ IsFiniteMeasure μ
Module: Mathlib.MeasureTheory.Measure.Trim

Goal state before:
pp: case refine_1
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
h : IsFiniteMeasure (μ.trim ⋯)
⊢ μ Set.univ < ∞

Tactic:
have h_univ := h.measure_univ_lt_top

Goal state after:
case refine_1
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
h : IsFiniteMeasure (μ.trim ⋯)
h_univ : (μ.trim ⋯) Set.univ < ∞
⊢ μ Set.univ < ∞
Module: Mathlib.MeasureTheory.Measure.Trim

Goal state before:
pp: case refine_2
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
h : IsFiniteMeasure μ
⊢ (μ.trim ⋯) Set.univ < ∞

Tactic:
have h_univ := h.measure_univ_lt_top

Goal state after:
case refine_2
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
h : IsFiniteMeasure μ
h_univ : μ Set.univ < ∞
⊢ (μ.trim ⋯) Set.univ < ∞