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

Goal state before:
pp: case pos
a b : ℝ
x y z : ↑(Icc a b)
s t : ↑unitInterval
hs : ↑s = 1
⊢ (1 - ↑s) * ↑x + ↑s * ((1 - ↑t) * ↑y + ↑t * ↑z) =
    (1 - ↑s * ↑t) * ((1 - ↑s * (1 - ↑t) / (1 - ↑s * ↑t)) * ↑x + ↑s * (1 - ↑t) / (1 - ↑s * ↑t) * ↑y) + ↑s * ↑t * ↑z

Tactic:
simp only [hs]
    by_cases ht : (t : ℝ) = 1
    · simp [ht]
    · have : (1 - t : ℝ) ≠ 0 := by grind
      field_simp
      simp

Goal state after:
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: α : Type u_2
x y : ℕ → α
n : ℕ
⊢ res x n = res y n ↔ ∀ ⦃m : ℕ⦄, m < n → x m = y m

Tactic:
constructor <;> intro h
  · induction n with
    | zero => simp
    | succ n ih =>
      intro m hm
      rw [Nat.lt_succ_iff_lt_or_eq] at hm
      simp only [res_succ, cons.injEq] at h
      rcases hm with hm | hm
      · exact ih h.2 hm
      rw [hm]
      exact h.1
  · induction n with
    | zero => simp
    | succ n ih =>
      simp only [res_succ, cons.injEq]
      refine ⟨h (Nat.lt_succ_self _), ih fun m hm => ?_⟩
      exact h (hm.trans (Nat.lt_succ_self _))

Goal state after:
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: α : Type u_2
⊢ Injective res

Tactic:
intro x y h
  ext n
  apply res_eq_res.mp _ (Nat.lt_succ_self _)
  rw [h]

Goal state after:
Module: Mathlib.Topology.MetricSpace.Gluing

Goal state before:
pp: ι : Type u_1
E : ι → Type u_2
inst✝ : (i : ι) → MetricSpace (E i)
i j : ι
h : i ≠ j
x : E i
y : E j
⊢ 1 ≤ dist x ⋯.some + 1 + dist ⋯.some y

Tactic:
linarith [@dist_nonneg _ _ x (Nonempty.some ⟨x⟩), @dist_nonneg _ _ (Nonempty.some ⟨y⟩) y]

Goal state after:
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: case mp
E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
s : Set ((n : ℕ) → E n)
hs : IsOpen[Pi.topologicalSpace] s
x : (n : ℕ) → E n
hx : x ∈ s
y : (n : ℕ) → E n
n : ℕ
h'x : x ∈ cylinder y n
h's : cylinder y n ⊆ s
⊢ ∃ ε > 0, ∀ (y : (n : ℕ) → E n), dist x y < ε → y ∈ s

Tactic:
← mem_cylinder_iff_eq.1 h'x

Goal state after:
case mp
E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
s : Set ((n : ℕ) → E n)
hs : IsOpen[Pi.topologicalSpace] s
x : (n : ℕ) → E n
hx : x ∈ s
y : (n : ℕ) → E n
n : ℕ
h'x : x ∈ cylinder y n
h's : cylinder x n ⊆ s
⊢ ∃ ε > 0, ∀ (y : (n : ℕ) → E n), dist x y < ε → y ∈ s
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
u : ℕ → (n : ℕ) → E n
hu : ∀ (N n m : ℕ), N ≤ n → N ≤ m → dist (u n) (u m) < (1 / 2) ^ N
i : ℕ
⊢ (fun x ↦ u i i) =ᶠ[atTop] fun i_1 ↦ u i_1 i

Tactic:
filter_upwards [Filter.Ici_mem_atTop i] with n hn

Goal state after:
E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
u : ℕ → (n : ℕ) → E n
hu : ∀ (N n m : ℕ), N ≤ n → N ≤ m → dist (u n) (u m) < (1 / 2) ^ N
i n : ℕ
hn : n ∈ Ici i
⊢ u i i = u n i
Module: Mathlib.Dynamics.Ergodic.MeasurePreserving

Goal state before:
pp: α : Type u_1
β : Type u_2
γ : Type u_3
inst✝² : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
μa : Measure α
μb : Measure β
μc : Measure γ
g : α → β
e : γ ≃ᵐ α
h : MeasurePreserving (⇑e) μc μa
⊢ MeasurePreserving (g ∘ ⇑e) μc μb ↔ MeasurePreserving g μa μb

Tactic:
by
  refine ⟨fun hg => ?_, fun hg => hg.comp h⟩
  convert! hg.comp (MeasurePreserving.symm e h)
  simp [Function.comp_assoc g e e.symm]

Goal state after:
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: case refine_1
E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
s : Set ((n : ℕ) → E n)
hs : IsClosed[Pi.topologicalSpace] s
hne : s.Nonempty
f : ((n : ℕ) → E n) → (n : ℕ) → E n := fun x ↦ if x ∈ s then x else ⋯.some
fs : ∀ x ∈ s, f x = x
⊢ range f = s

pp: case refine_2
E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
s : Set ((n : ℕ) → E n)
hs : IsClosed[Pi.topologicalSpace] s
hne : s.Nonempty
f : ((n : ℕ) → E n) → (n : ℕ) → E n := fun x ↦ if x ∈ s then x else ⋯.some
fs : ∀ x ∈ s, f x = x
⊢ LipschitzWith 1 f

Tactic:
· apply Subset.antisymm
    · rintro x ⟨y, rfl⟩
      by_cases hy : y ∈ s
      · rwa [fs y hy]
      simpa [f, if_neg hy] using! (inter_cylinder_longestPrefix_nonempty hs hne y).choose_spec.1
    · intro x hx
      rw [← fs x hx]
      exact mem_range_self _

Goal state after:
case refine_2
E : ℕ → Type u_1
inst✝¹ : (n : ℕ) → TopologicalSpace (E n)
inst✝ : ∀ (n : ℕ), DiscreteTopology (E n)
s : Set ((n : ℕ) → E n)
hs : IsClosed[Pi.topologicalSpace] s
hne : s.Nonempty
f : ((n : ℕ) → E n) → (n : ℕ) → E n := fun x ↦ if x ∈ s then x else ⋯.some
fs : ∀ x ∈ s, f x = x
⊢ LipschitzWith 1 f
Module: Mathlib.MeasureTheory.Measure.MutuallySingular

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
ν : Measure α
ι : Type u_2
inst✝ : Countable ι
μ : ι → Measure α
⊢ sum μ ⟂ₘ ν ↔ ∀ (i : ι), μ i ⟂ₘ ν

Tactic:
refine ⟨fun h i => h.mono (le_sum _ _) le_rfl, fun H => ?_⟩

Goal state after:
α : Type u_1
m0 : MeasurableSpace α
ν : Measure α
ι : Type u_2
inst✝ : Countable ι
μ : ι → Measure α
H : ∀ (i : ι), μ i ⟂ₘ ν
⊢ sum μ ⟂ₘ ν
Module: Mathlib.MeasureTheory.Measure.Count

Goal state before:
pp: α : Type u_1
inst✝ : MeasurableSpace α
s : Finset α
hs : MeasurableSet ↑s
⊢ count ↑s = ↑(#s)

Tactic:
by simp [count_apply hs]

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

Goal state before:
pp: α : Type u_1
inst✝² : MeasurableSpace α
inst✝¹ : Countable α
inst✝ : MeasurableSingletonClass α
μ : Measure α
s : Set α
hs : MeasurableSet s
⊢ (sum fun a ↦ μ {a} • dirac a) s = μ s

Tactic:
μ.sum_smul_dirac

Goal state after:
α : Type u_1
inst✝² : MeasurableSpace α
inst✝¹ : Countable α
inst✝ : MeasurableSingletonClass α
μ : Measure α
s : Set α
hs : MeasurableSet s
⊢ μ s = μ s
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: α : Type u_2
inst✝³ : MetricSpace α
inst✝² : CompleteSpace α
inst✝¹ : SecondCountableTopology α
inst✝ : Nonempty α
this : MetricSpace (ℕ → ℕ) := metricSpaceNatNat
⊢ ∃ f, Continuous[_, PseudoMetricSpace.toUniformSpace.toTopologicalSpace] f ∧ Surjective f

Tactic:
have I0 : (0 : ℝ) < 1 / 2 := by simp

Goal state after:
α : Type u_2
inst✝³ : MetricSpace α
inst✝² : CompleteSpace α
inst✝¹ : SecondCountableTopology α
inst✝ : Nonempty α
this : MetricSpace (ℕ → ℕ) := metricSpaceNatNat
I0 : 0 < 1 / 2
⊢ ∃ f, Continuous[_, PseudoMetricSpace.toUniformSpace.toTopologicalSpace] f ∧ Surjective f
Module: Mathlib.MeasureTheory.Measure.GiryMonad

Goal state before:
pp: α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
μ : α → Measure β
inst✝ : ∀ (a : α), IsFiniteMeasure (μ a)
S : Set (Set β)
hgen : mβ = MeasurableSpace.generateFrom S
hpi : IsPiSystem S
h_basic : ∀ s ∈ S, Measurable fun a ↦ (μ a) s
h_univ : Measurable fun a ↦ (μ a) univ
⊢ Measurable μ

Tactic:
measurable_measure

Goal state after:
α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
μ : α → Measure β
inst✝ : ∀ (a : α), IsFiniteMeasure (μ a)
S : Set (Set β)
hgen : mβ = MeasurableSpace.generateFrom S
hpi : IsPiSystem S
h_basic : ∀ s ∈ S, Measurable fun a ↦ (μ a) s
h_univ : Measurable fun a ↦ (μ a) univ
⊢ ∀ (s : Set β), MeasurableSet s → Measurable fun b ↦ (μ b) s
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: case left
E : ℕ → Type u_1
ι : Type u_2
inst✝¹ : Encodable ι
F : ι → Type u_3
inst✝ : (i : ι) → PseudoEMetricSpace (F i)
⊢ ∀ (i : ℝ≥0∞), 0 < i → {p | edist p.1 p.2 < i} ∈ ⨅ i, ⨅ i_2, ⨅ (_ : 0 < i_2), 𝓟 {a | edist (a.1 i) (a.2 i) < i_2}

Tactic:
intro ε hε
      obtain ⟨K, hK⟩ : ∃ K : Finset ι, ∑' i : {j // j ∉ K}, 2⁻¹ ^ encode (i : ι) < ε / 2 :=
        ((tendsto_order.1 <| ENNReal.tendsto_tsum_compl_atTop_zero
          (tsum_geometric_encode_lt_top ENNReal.one_half_lt_one).ne).2 _
            <| by simpa using hε.ne').exists
      obtain ⟨δ, δpos, hδ⟩ : ∃ δ, 0 < δ ∧ δ * K.card < ε / 2 :=
        ENNReal.exists_pos_mul_lt (by simp) (by simpa using hε.ne')
      apply @mem_iInf_of_iInter _ _ _ _ _ K.finite_toSet fun i =>
          {p : (∀ i : ι, F i) × ∀ i : ι, F i | edist (p.fst i) (p.snd i) < δ}
      · rintro ⟨i, hi⟩
        refine mem_iInf_of_mem δ (mem_iInf_of_mem δpos ?_)
        simp only [mem_principal, Subset.rfl]
      · rintro ⟨x, y⟩ hxy
        simp only [mem_iInter, mem_ofPred_eq, SetCoe.forall, Finset.mem_coe] at hxy
        calc
          edist x y = ∑' i : ι, min (2⁻¹ ^ encode i) (edist (x i) (y i)) := rfl
          _ = ∑ i ∈ K, min (2⁻¹ ^ encode i) (edist (x i) (y i)) +
                ∑' i : ↑(K : Set ι)ᶜ, min (2⁻¹ ^ encode (i : ι)) (edist (x i) (y i)) :=
            (ENNReal.sum_add_tsum_compl ..).symm
          _ ≤ ∑ i ∈ K, edist (x i) (y i) + ∑' i : ↑(K : Set ι)ᶜ, 2⁻¹ ^ encode (i : ι) := by
            gcongr
            · apply min_le_right
            · apply min_le_left
          _ < ∑ _i ∈ K, δ + ε / 2 := by
            refine ENNReal.add_lt_add_of_le_of_lt (by simpa using fun i hi ↦ (hxy i hi).ne_top) ?_
              hK
            gcongr with i hi
            exact (hxy i hi).le
          _ ≤ ε / 2 + ε / 2 := by gcongr; simpa [mul_comm] using hδ.le
          _ = ε := ENNReal.add_halves _

Goal state after:
Module: Mathlib.Topology.MetricSpace.PiNat

Goal state before:
pp: case right
E : ℕ → Type u_1
ι : Type u_2
inst✝¹ : Encodable ι
F : ι → Type u_3
inst✝ : (i : ι) → PseudoEMetricSpace (F i)
⊢ ∀ (i : ι) (i_1 : ℝ≥0∞), 0 < i_1 → {a | edist (a.1 i) (a.2 i) < i_1} ∈ ⨅ ε, ⨅ (_ : 0 < ε), 𝓟 {p | edist p.1 p.2 < ε}

Tactic:
intro i ε hε₀
      have : (0 : ℝ≥0∞) < 2⁻¹ ^ encode i := ENNReal.pow_pos (by norm_num) _
      refine mem_iInf_of_mem (min (2⁻¹ ^ encode i) ε) <| mem_iInf_of_mem (by positivity) ?_
      simp only [and_imp, Prod.forall, ofPred_subset_ofPred, lt_min_iff, mem_principal]
      intro x y hn
      exact (edist_le_edist_pi_of_edist_lt hn).trans_lt

Goal state after:
Module: Mathlib.MeasureTheory.Group.Convolution

Goal state before:
pp: M : Type u_1
inst✝⁵ : Monoid M
inst✝⁴ : MeasurableSpace M
inst✝³ : MeasurableMul₂ M
μ ν ρ : Measure M
inst✝² : SFinite μ
inst✝¹ : SFinite ν
inst✝ : SFinite ρ
⊢ (μ + ν) ∗ₘ ρ = μ ∗ₘ ρ + ν ∗ₘ ρ

Tactic:
by
  unfold mconv
  rw [add_prod, Measure.map_add]
  fun_prop

Goal state after:
Module: Mathlib.GroupTheory.Complement

Goal state before:
pp: case e'_2.mpr
G : Type u_1
inst✝ : Group G
S T : Set G
g : G
x : ↑S × ↑T
hx : ↑x.1 * ↑x.2 = g
hx' : ∀ (y : ↑S × ↑T), (fun x ↦ ↑x.1 * ↑x.2 = g) y → y = x
⊢ ∃! t, g * (↑t)⁻¹ ∈ S

Tactic:
· exact ⟨x.2, by simp [← hx], fun y hy ↦ (Prod.ext_iff.1 <| by simpa using hx' (⟨_, hy⟩, y)).2⟩

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

Goal state before:
pp: α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < (map f μ) U
⊢ ∃ K ⊆ U, pb K ∧ r < (map f μ) K

Tactic:
map_apply_of_aemeasurable hf (hB₂ _ hU)

Goal state after:
α : Type u_2
β : Type u_3
inst✝¹ : MeasurableSpace α
inst✝ : MeasurableSpace β
μ : Measure α
pa qa : Set α → Prop
H : μ.InnerRegularWRT pa qa
f : α → β
hf : AEMeasurable f μ
pb qb : Set β → Prop
hAB : ∀ (U : Set β), qb U → qa (f ⁻¹' U)
hAB' : ∀ (K : Set α), pa K → pb (f '' K)
hB₂ : ∀ (U : Set β), qb U → MeasurableSet U
U : Set β
hU : qb U
r : ℝ≥0∞
hr : r < μ (f ⁻¹' U)
⊢ ∃ K ⊆ U, pb K ∧ r < (map f μ) K
Module: Mathlib.GroupTheory.Complement

Goal state before:
pp: G : Type u_1
inst✝¹ : Group G
H : Subgroup G
α : Type u_2
inst✝ : MulAction G α
a : α
h1 : ∀ (h : ↥H), h • a = a → h = 1
h2 : ∀ (g : G), ∃ h, h • g • a = a
g : G
⊢ ∃! x, ↑x.1 * ↑x.2 = g

Tactic:
obtain ⟨h, hh⟩ := h2 g

Goal state after:
G : Type u_1
inst✝¹ : Group G
H : Subgroup G
α : Type u_2
inst✝ : MulAction G α
a : α
h1 : ∀ (h : ↥H), h • a = a → h = 1
h2 : ∀ (g : G), ∃ h, h • g • a = a
g : G
h : ↥H
hh : h • g • a = a
⊢ ∃! x, ↑x.1 * ↑x.2 = g
Module: Mathlib.MeasureTheory.Group.Action

Goal state before:
pp: G : Type u
α : Type w
m : MeasurableSpace α
inst✝² : Group G
inst✝¹ : MulAction G α
μ : Measure α
inst✝ : SMulInvariantMeasure G α μ
c : G
s t : Set α
⊢ μ (c • (s ∩ c⁻¹ • t)) = μ (c • s ∩ t)

Tactic:
smul_set_inter,

Goal state after:
G : Type u
α : Type w
m : MeasurableSpace α
inst✝² : Group G
inst✝¹ : MulAction G α
μ : Measure α
inst✝ : SMulInvariantMeasure G α μ
c : G
s t : Set α
⊢ μ (c • s ∩ c • c⁻¹ • t) = μ (c • s ∩ t)
Module: Mathlib.MeasureTheory.Measure.Prod

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : MeasurableSpace β
μ : Measure α
ν : Measure β
inst✝¹ : SFinite ν
inst✝ : SFinite μ
s : Set α
t : Set β
h : NullMeasurableSet (s ×ˢ t) (μ.prod ν)
ht : ν t ≠ 0
⊢ NullMeasurableSet (t ×ˢ s) (ν.prod μ)

Tactic:
rw [← preimage_swap_prod]

Goal state after:
α : Type u_1
β : Type u_2
inst✝³ : MeasurableSpace α
inst✝² : MeasurableSpace β
μ : Measure α
ν : Measure β
inst✝¹ : SFinite ν
inst✝ : SFinite μ
s : Set α
t : Set β
h : NullMeasurableSet (s ×ˢ t) (μ.prod ν)
ht : ν t ≠ 0
⊢ NullMeasurableSet (Prod.swap ⁻¹' s ×ˢ t) (ν.prod μ)
Module: Mathlib.MeasureTheory.Group.Measure

Goal state before:
pp: G : Type u_1
H✝ : Type u_2
inst✝⁹ : MeasurableSpace G
inst✝⁸ : MeasurableSpace H✝
inst✝⁷ : Mul G
μ : Measure G
inst✝⁶ : MeasurableMul G
inst✝⁵ : μ.IsMulRightInvariant
inst✝⁴ : SFinite μ
H : Type u_3
inst✝³ : Mul H
mH : MeasurableSpace H
ν : Measure H
inst✝² : MeasurableMul H
inst✝¹ : ν.IsMulRightInvariant
inst✝ : SFinite ν
⊢ (μ.prod ν).IsMulRightInvariant

Tactic:
by
  constructor
  rintro ⟨g, h⟩
  change map (Prod.map (· * g) (· * h)) (μ.prod ν) = μ.prod ν
  rw [← map_prod_map _ _ (measurable_mul_const g) (measurable_mul_const h),
    map_mul_right_eq_self μ g, map_mul_right_eq_self ν h]

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

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝² : MeasurableSpace α
inst✝¹ : MeasurableSpace β
μ : Measure α
ν : Measure β
inst✝ : SFinite ν
f : α → ℝ≥0∞
g : β → ℝ≥0∞
hf : AEMeasurable f μ
hg : AEMeasurable g ν
⊢ ∫⁻ (z : α × β), f z.1 * g z.2 ∂μ.prod ν = (∫⁻ (x : α), f x ∂μ) * ∫⁻ (y : β), g y ∂ν

Tactic:
rw [lintegral_prod _ (by fun_prop)]
  simp [lintegral_lintegral_mul hf hg]

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

Goal state before:
pp: case pos
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝² : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
X : α → β
Y : α → γ
μ : Measure α
hY : AEMeasurable Y μ
hX : AEMeasurable X μ
s : Set β
hs : MeasurableSet s
⊢ μ ((fun x ↦ (X x, Y x)) ⁻¹' s ×ˢ univ) = μ (X ⁻¹' s)

Tactic:
mk_preimage_prod,

Goal state after:
case pos
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝² : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
X : α → β
Y : α → γ
μ : Measure α
hY : AEMeasurable Y μ
hX : AEMeasurable X μ
s : Set β
hs : MeasurableSet s
⊢ μ (X ⁻¹' s ∩ Y ⁻¹' univ) = μ (X ⁻¹' s)
Module: Mathlib.MeasureTheory.Measure.Prod

Goal state before:
pp: case pos
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝² : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
X : α → β
Y : α → γ
μ : Measure α
hX : AEMeasurable X μ
hY : AEMeasurable Y μ
s : Set γ
hs : MeasurableSet s
⊢ μ ((fun x ↦ (X x, Y x)) ⁻¹' univ ×ˢ s) = μ (Y ⁻¹' s)

Tactic:
mk_preimage_prod,

Goal state after:
case pos
α : Type u_1
β : Type u_2
γ : Type u_3
inst✝² : MeasurableSpace α
inst✝¹ : MeasurableSpace β
inst✝ : MeasurableSpace γ
X : α → β
Y : α → γ
μ : Measure α
hX : AEMeasurable X μ
hY : AEMeasurable Y μ
s : Set γ
hs : MeasurableSet s
⊢ μ (X ⁻¹' univ ∩ Y ⁻¹' s) = μ (Y ⁻¹' s)
Module: Mathlib.MeasureTheory.Group.Prod

Goal state before:
pp: G : Type u_1
inst✝⁵ : MeasurableSpace G
inst✝⁴ : Group G
inst✝³ : MeasurableMul₂ G
μ : Measure G
inst✝² : SFinite μ
inst✝¹ : MeasurableInv G
inst✝ : μ.IsMulLeftInvariant
s : Set G
hsm : MeasurableSet s
hμs : μ s = 0
hf : Measurable fun z ↦ (z.2 * z.1, z.1⁻¹)
hsm' : MeasurableSet (s⁻¹ ×ˢ s⁻¹)
⊢ ∫⁻ (y : G), μ ((fun x ↦ (y * x, x⁻¹)) ⁻¹' s⁻¹ ×ˢ s⁻¹) ∂μ = 0

Tactic:
mk_preimage_prod,

Goal state after:
G : Type u_1
inst✝⁵ : MeasurableSpace G
inst✝⁴ : Group G
inst✝³ : MeasurableMul₂ G
μ : Measure G
inst✝² : SFinite μ
inst✝¹ : MeasurableInv G
inst✝ : μ.IsMulLeftInvariant
s : Set G
hsm : MeasurableSet s
hμs : μ s = 0
hf : Measurable fun z ↦ (z.2 * z.1, z.1⁻¹)
hsm' : MeasurableSet (s⁻¹ ×ˢ s⁻¹)
⊢ ∫⁻ (y : G), μ (HMul.hMul y ⁻¹' s⁻¹ ∩ Inv.inv ⁻¹' s⁻¹) ∂μ = 0
Module: Mathlib.MeasureTheory.Group.Prod

Goal state before:
pp: G : Type u_1
inst✝⁷ : MeasurableSpace G
inst✝⁶ : Group G
inst✝⁵ : MeasurableMul₂ G
μ ν : Measure G
inst✝⁴ : SFinite ν
inst✝³ : SFinite μ
inst✝² : MeasurableInv G
inst✝¹ : μ.IsMulLeftInvariant
inst✝ : ν.IsMulLeftInvariant
hν : ν ≠ 0
s : Set G
sm : MeasurableSet s
hνs : ν s = 0
h1 : μ s * ∫⁻ (y : G), 1 y ∂ν = ∫⁻ (x : G), ν ((fun z ↦ z * x) ⁻¹' s) * 1 x⁻¹ ∂μ
⊢ μ s = 0

Tactic:
simp_rw [Pi.one_apply, lintegral_one, mul_one, (measure_mul_right_null ν _).mpr hνs,
    lintegral_zero, mul_eq_zero (M₀ := ℝ≥0∞), measure_univ_eq_zero.not.mpr hν, or_false] at h1

Goal state after:
G : Type u_1
inst✝⁷ : MeasurableSpace G
inst✝⁶ : Group G
inst✝⁵ : MeasurableMul₂ G
μ ν : Measure G
inst✝⁴ : SFinite ν
inst✝³ : SFinite μ
inst✝² : MeasurableInv G
inst✝¹ : μ.IsMulLeftInvariant
inst✝ : ν.IsMulLeftInvariant
hν : ν ≠ 0
s : Set G
sm : MeasurableSet s
hνs : ν s = 0
h1 : μ s = 0
⊢ μ s = 0
Module: Mathlib.MeasureTheory.Measure.WithDensity

Goal state before:
pp: α : Type u_1
m0 : MeasurableSpace α
f : α → ℝ≥0∞
hf : Measurable f
a : α
s : Set α
hs : MeasurableSet s
⊢ ((dirac a).withDensity f) s = (f a • dirac a) s

Tactic:
classical
  simp [withDensity_apply f hs, setLIntegral_dirac' hf hs, dirac_apply' _ hs,
    Set.indicator]

Goal state after:
Module: Mathlib.MeasureTheory.Function.Egorov

Goal state before:
pp: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
inst✝³ : PseudoEMetricSpace β
μ : Measure α
s : Set α
ε : ℝ
f : ι → α → β
g : α → β
inst✝² : SemilatticeSup ι
inst✝¹ : Nonempty ι
inst✝ : Countable ι
hε : 0 < ε
hf : ∀ (n : ι), Measurable fun a ↦ edist (f n a) (g a)
hsm : MeasurableSet s
hs : μ s ≠ ∞
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → Tendsto (fun n ↦ f n x) atTop (𝓝 (g x))
n : ℕ
N : ι
hN :
  ∀ n_1 ≥ N, μ (s ∩ notConvergentSeq f g n n_1) ∈ Icc (0 - ENNReal.ofReal (ε * 2⁻¹ ^ n)) (ENNReal.ofReal (ε * 2⁻¹ ^ n))
⊢ ∃ j, μ (s ∩ notConvergentSeq f g n j) ≤ ENNReal.ofReal (ε * 2⁻¹ ^ n)

Tactic:
exact ⟨N, (hN N le_rfl).2⟩

Goal state after:
Module: Mathlib.MeasureTheory.Function.Egorov

Goal state before:
pp: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
inst✝³ : PseudoEMetricSpace β
μ : Measure α
s : Set α
ε : ℝ
f : ι → α → β
g : α → β
inst✝² : SemilatticeSup ι
inst✝¹ : Nonempty ι
inst✝ : Countable ι
hε : 0 < ε
hf : ∀ (n : ι), Measurable fun a ↦ edist (f n a) (g a)
hsm : MeasurableSet s
hs : μ s ≠ ∞
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → Tendsto (fun n ↦ f n x) atTop (𝓝 (g x))
⊢ ENNReal.ofReal (ε / 2) * ENNReal.ofReal 2 ≤ ENNReal.ofReal ε

pp: case hf_nonneg
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
inst✝³ : PseudoEMetricSpace β
μ : Measure α
s : Set α
ε : ℝ
f : ι → α → β
g : α → β
inst✝² : SemilatticeSup ι
inst✝¹ : Nonempty ι
inst✝ : Countable ι
hε : 0 < ε
hf : ∀ (n : ι), Measurable fun a ↦ edist (f n a) (g a)
hsm : MeasurableSet s
hs : μ s ≠ ∞
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → Tendsto (fun n ↦ f n x) atTop (𝓝 (g x))
⊢ ∀ (n : ℕ), 0 ≤ 2⁻¹ ^ n

pp: case hf
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
inst✝³ : PseudoEMetricSpace β
μ : Measure α
s : Set α
ε : ℝ
f : ι → α → β
g : α → β
inst✝² : SemilatticeSup ι
inst✝¹ : Nonempty ι
inst✝ : Countable ι
hε : 0 < ε
hf : ∀ (n : ι), Measurable fun a ↦ edist (f n a) (g a)
hsm : MeasurableSet s
hs : μ s ≠ ∞
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → Tendsto (fun n ↦ f n x) atTop (𝓝 (g x))
⊢ Summable (HPow.hPow 2⁻¹)

Tactic:
← ENNReal.ofReal_mul (half_pos hε).le,

Goal state after:
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
inst✝³ : PseudoEMetricSpace β
μ : Measure α
s : Set α
ε : ℝ
f : ι → α → β
g : α → β
inst✝² : SemilatticeSup ι
inst✝¹ : Nonempty ι
inst✝ : Countable ι
hε : 0 < ε
hf : ∀ (n : ι), Measurable fun a ↦ edist (f n a) (g a)
hsm : MeasurableSet s
hs : μ s ≠ ∞
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → Tendsto (fun n ↦ f n x) atTop (𝓝 (g x))
⊢ ENNReal.ofReal (ε / 2 * 2) ≤ ENNReal.ofReal ε

case hf_nonneg
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
inst✝³ : PseudoEMetricSpace β
μ : Measure α
s : Set α
ε : ℝ
f : ι → α → β
g : α → β
inst✝² : SemilatticeSup ι
inst✝¹ : Nonempty ι
inst✝ : Countable ι
hε : 0 < ε
hf : ∀ (n : ι), Measurable fun a ↦ edist (f n a) (g a)
hsm : MeasurableSet s
hs : μ s ≠ ∞
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → Tendsto (fun n ↦ f n x) atTop (𝓝 (g x))
⊢ ∀ (n : ℕ), 0 ≤ 2⁻¹ ^ n

case hf
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
inst✝³ : PseudoEMetricSpace β
μ : Measure α
s : Set α
ε : ℝ
f : ι → α → β
g : α → β
inst✝² : SemilatticeSup ι
inst✝¹ : Nonempty ι
inst✝ : Countable ι
hε : 0 < ε
hf : ∀ (n : ι), Measurable fun a ↦ edist (f n a) (g a)
hsm : MeasurableSet s
hs : μ s ≠ ∞
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → Tendsto (fun n ↦ f n x) atTop (𝓝 (g x))
⊢ Summable (HPow.hPow 2⁻¹)
Module: Mathlib.MeasureTheory.Function.Egorov

Goal state before:
pp: α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
inst✝³ : PseudoEMetricSpace β
μ : Measure α
s : Set α
ε : ℝ
f : ι → α → β
g : α → β
inst✝² : SemilatticeSup ι
inst✝¹ : Nonempty ι
inst✝ : Countable ι
hε : 0 < ε
hf : ∀ (n : ι), Measurable fun a ↦ edist (f n a) (g a)
hsm : MeasurableSet s
hs : μ s ≠ ∞
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → Tendsto (fun n ↦ f n x) atTop (𝓝 (g x))
⊢ iUnionNotConvergentSeq hε hf hsm hs hfg ⊆ s

Tactic:
rw [iUnionNotConvergentSeq, ← Set.inter_iUnion]

Goal state after:
α : Type u_1
β : Type u_2
ι : Type u_3
m : MeasurableSpace α
inst✝³ : PseudoEMetricSpace β
μ : Measure α
s : Set α
ε : ℝ
f : ι → α → β
g : α → β
inst✝² : SemilatticeSup ι
inst✝¹ : Nonempty ι
inst✝ : Countable ι
hε : 0 < ε
hf : ∀ (n : ι), Measurable fun a ↦ edist (f n a) (g a)
hsm : MeasurableSet s
hs : μ s ≠ ∞
hfg : ∀ᵐ (x : α) ∂μ, x ∈ s → Tendsto (fun n ↦ f n x) atTop (𝓝 (g x))
⊢ s ∩ ⋃ i, notConvergentSeq f g i (notConvergentSeqLTIndex ⋯ hf hsm hs hfg i) ⊆ s
Module: Mathlib.MeasureTheory.Measure.WithDensity

Goal state before:
pp: case refine_1
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
inst✝ : SigmaFinite μ
f : α → ℝ≥0
n : ℕ
⊢ (μ.withDensity fun x ↦ ↑(f x)) (spanningSets μ n ∩ f ⁻¹' Iic ↑n) < ∞

Tactic:
rw [withDensity_apply']

Goal state after:
case refine_1
α : Type u_1
m0 : MeasurableSpace α
μ : Measure α
inst✝ : SigmaFinite μ
f : α → ℝ≥0
n : ℕ
⊢ ∫⁻ (a : α) in spanningSets μ n ∩ f ⁻¹' Iic ↑n, ↑(f a) ∂μ < ∞
Module: Mathlib.MeasureTheory.Function.L1Space.HasFiniteIntegral

Goal state before:
pp: α : Type u_1
ε : Type u_4
m : MeasurableSpace α
μ : Measure α
inst✝ : ENorm ε
f : α → ε
h : HasFiniteIntegral f μ
s : Set α
⊢ HasFiniteIntegral f (μ.restrict s)

Tactic:
refine lt_of_le_of_lt ?_ h

Goal state after:
α : Type u_1
ε : Type u_4
m : MeasurableSpace α
μ : Measure α
inst✝ : ENorm ε
f : α → ε
h : HasFiniteIntegral f μ
s : Set α
⊢ ∫⁻ (a : α) in s, ‖f a‖ₑ ∂μ ≤ ∫⁻ (a : α), ‖f a‖ₑ ∂μ
Module: Mathlib.Analysis.Normed.Group.Hom

Goal state before:
pp: case refine_2
V₁ : Type u_2
V₂ : Type u_3
inst✝¹ : SeminormedAddCommGroup V₁
inst✝ : SeminormedAddCommGroup V₂
f : NormedAddGroupHom V₁ V₂
K : AddSubgroup V₂
C : ℝ
h : f.SurjectiveOnWith K C
⊢ C ≤ |C| + 1

Tactic:
linarith [le_abs_self C]

Goal state after: