mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Analysis.Calculus.DerivativeTest

Goal state before:
pp: f : ℝ → ℝ
b c : ℝ
hb : ContinuousAt f b
hc : ContinuousAt f c
hd₀ : DifferentiableOn ℝ f (Iio b)
hd₁ : DifferentiableOn ℝ f (Ioo b c)
h₀ : ∀ x ∈ Iio b, deriv f x ≤ 0
h₁ : ∀ x ∈ Ioo b c, 0 ≤ deriv f x
⊢ IsMinOn f (Iic c) b

Tactic:
by
  refine isMinOn_Iic_of_anti_mono ?_ ?_
  · apply antitoneOn_of_deriv_nonpos (convex_Iic b) (continuousOn_Iic hb hd₀) <;> simp_all
  · apply monotoneOn_of_deriv_nonneg (convex_Icc b c) (continuousOn_Icc hb hc hd₁) <;> simp_all

Goal state after:
Module: Mathlib.MeasureTheory.Covering.Besicovitch

Goal state before:
pp: α : Type u_1
inst✝⁶ : MetricSpace α
inst✝⁵ : SecondCountableTopology α
inst✝⁴ : MeasurableSpace α
inst✝³ : OpensMeasurableSpace α
inst✝² : HasBesicovitchCovering α
μ : Measure α
inst✝¹ : SFinite μ
inst✝ : μ.OuterRegular
ε : ℝ≥0∞
hε : ε ≠ 0
f : α → Set ℝ
s : Set α
hf : ∀ x ∈ s, ∀ δ > 0, (f x ∩ Ioo 0 δ).Nonempty
⊢ ε / 2 ≠ 0

Tactic:
simpa only [or_false, Ne, ENNReal.div_eq_zero_iff, ENNReal.ofNat_ne_top] using hε

Goal state after:
Module: Mathlib.Analysis.Calculus.VectorField

Goal state before:
pp: 𝕜 : Type u_1
inst✝⁴ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace 𝕜 E
F : Type u_3
inst✝¹ : NormedAddCommGroup F
inst✝ : NormedSpace 𝕜 F
V W : E → E
s : Set E
x : E
f : E → F
n : ℕ∞ω
hf : ContDiffWithinAt 𝕜 n f s x
hn : minSmoothness 𝕜 2 ≤ n
hs : UniqueDiffOn 𝕜 s
hxs' : x ∈ closure[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] (interior s)
hxs : x ∈ s
hW : DifferentiableWithinAt 𝕜 W s x
hV : DifferentiableWithinAt 𝕜 V s x
⊢ (fderivWithin 𝕜 f s x) (lieBracketWithin 𝕜 V W s x) =
    (fderivWithin 𝕜 (fun x ↦ (fderivWithin 𝕜 f s x) (W x)) s x) (V x) -
      (fderivWithin 𝕜 (fun x ↦ (fderivWithin 𝕜 f s x) (V x)) s x) (W x)

Tactic:
by
  apply fderivWithin_apply_lieBracket_of_isSymmSndFDerivWithinAt <;> try assumption
  exacts [hf.of_le <| le_minSmoothness.trans hn, hf.isSymmSndFDerivWithinAt hn hs hxs' hxs]

Goal state after:
Module: Mathlib.Analysis.Calculus.IteratedDeriv.FaaDiBruno

Goal state before:
pp: 𝕜 : Type u_1
E : Type u_2
inst✝² : NontriviallyNormedField 𝕜
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
g : 𝕜 → E
f : 𝕜 → 𝕜
x : 𝕜
hg : ContDiffAt 𝕜 3 g (f x)
hf : ContDiffAt 𝕜 3 f x
⊢ iteratedDeriv 3 (g ∘ f) x =
    deriv f x ^ 3 • iteratedDeriv 3 g (f x) + 3 • iteratedDeriv 2 f x • deriv f x • iteratedDeriv 2 g (f x) +
      iteratedDeriv 3 f x • deriv g (f x)

Tactic:
simp only [← iteratedDerivWithin_univ, ← derivWithin_univ]
  exact iteratedDerivWithin_scomp_three hg hf uniqueDiffOn_univ uniqueDiffOn_univ (mem_univ _)
    (mapsTo_univ _ _)

Goal state after:
Module: Mathlib.Analysis.Calculus.LagrangeMultipliers

Goal state before:
pp: E : Type u_1
F : Type u_2
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : CompleteSpace E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
f : E → F
φ : E → ℝ
x₀ : E
f' : E →L[ℝ] F
φ' : StrongDual ℝ E
hextr : IsLocalExtrOn φ {x | f x = f x₀} x₀
hf' : HasStrictFDerivAt f f' x₀
hφ' : HasStrictFDerivAt φ φ' x₀
htop : (↑(f'.prod φ')).range = ⊤
fφ : E → F × ℝ := fun x ↦ (f x, φ x)
⊢ map φ (𝓝[f ⁻¹' {f x₀}] x₀) = 𝓝 (φ x₀)

Tactic:
change map (Prod.snd ∘ fφ) (𝓝[fφ ⁻¹' {p | p.1 = f x₀}] x₀) = 𝓝 (φ x₀)

Goal state after:
E : Type u_1
F : Type u_2
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : CompleteSpace E
inst✝² : NormedAddCommGroup F
inst✝¹ : NormedSpace ℝ F
inst✝ : CompleteSpace F
f : E → F
φ : E → ℝ
x₀ : E
f' : E →L[ℝ] F
φ' : StrongDual ℝ E
hextr : IsLocalExtrOn φ {x | f x = f x₀} x₀
hf' : HasStrictFDerivAt f f' x₀
hφ' : HasStrictFDerivAt φ φ' x₀
htop : (↑(f'.prod φ')).range = ⊤
fφ : E → F × ℝ := fun x ↦ (f x, φ x)
⊢ map (Prod.snd ∘ fφ) (𝓝[fφ ⁻¹' {p | p.1 = f x₀}] x₀) = 𝓝 (φ x₀)
Module: Mathlib.Analysis.Calculus.LHopital

Goal state before:
pp: case refine_1
a b : ℝ
l : Filter ℝ
f f' g g' : ℝ → ℝ
hab : a < b
hff' : ∀ x ∈ Ioo a b, HasDerivAt f (f' x) x
hgg' : ∀ x ∈ Ioo a b, HasDerivAt g (g' x) x
hcf : ContinuousOn f (Ioc a b)
hcg : ContinuousOn g (Ioc a b)
hg' : ∀ x ∈ Ioo a b, g' x ≠ 0
hfb : f b = 0
hgb : g b = 0
hdiv : Tendsto (fun x ↦ f' x / g' x) (𝓝[<] b) l
⊢ Tendsto f (𝓝[<] b) (𝓝 (f b))

Tactic:
← nhdsWithin_Ioo_eq_nhdsLT hab

Goal state after:
case refine_1
a b : ℝ
l : Filter ℝ
f f' g g' : ℝ → ℝ
hab : a < b
hff' : ∀ x ∈ Ioo a b, HasDerivAt f (f' x) x
hgg' : ∀ x ∈ Ioo a b, HasDerivAt g (g' x) x
hcf : ContinuousOn f (Ioc a b)
hcg : ContinuousOn g (Ioc a b)
hg' : ∀ x ∈ Ioo a b, g' x ≠ 0
hfb : f b = 0
hgb : g b = 0
hdiv : Tendsto (fun x ↦ f' x / g' x) (𝓝[<] b) l
⊢ Tendsto f (𝓝[Ioo a b] b) (𝓝 (f b))
Module: Mathlib.Analysis.Calculus.LHopital

Goal state before:
pp: case refine_2
a b : ℝ
l : Filter ℝ
f f' g g' : ℝ → ℝ
hab : a < b
hff' : ∀ x ∈ Ioo a b, HasDerivAt f (f' x) x
hgg' : ∀ x ∈ Ioo a b, HasDerivAt g (g' x) x
hcf : ContinuousOn f (Ioc a b)
hcg : ContinuousOn g (Ioc a b)
hg' : ∀ x ∈ Ioo a b, g' x ≠ 0
hfb : f b = 0
hgb : g b = 0
hdiv : Tendsto (fun x ↦ f' x / g' x) (𝓝[<] b) l
⊢ Tendsto g (𝓝[<] b) (𝓝 (g b))

Tactic:
← nhdsWithin_Ioo_eq_nhdsLT hab

Goal state after:
case refine_2
a b : ℝ
l : Filter ℝ
f f' g g' : ℝ → ℝ
hab : a < b
hff' : ∀ x ∈ Ioo a b, HasDerivAt f (f' x) x
hgg' : ∀ x ∈ Ioo a b, HasDerivAt g (g' x) x
hcf : ContinuousOn f (Ioc a b)
hcg : ContinuousOn g (Ioc a b)
hg' : ∀ x ∈ Ioo a b, g' x ≠ 0
hfb : f b = 0
hgb : g b = 0
hdiv : Tendsto (fun x ↦ f' x / g' x) (𝓝[<] b) l
⊢ Tendsto g (𝓝[Ioo a b] b) (𝓝 (g b))
Module: Mathlib.MeasureTheory.Function.Jacobian

Goal state before:
pp: E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
A : E →L[ℝ] E
m : ℝ≥0
hm : ENNReal.ofReal |A.det| < ↑m
d : ℝ≥0∞ := ENNReal.ofReal |A.det|
HC : IsCompact (⇑A '' closedBall 0 1)
L0 : Tendsto (fun ε ↦ μ (cthickening ε (⇑A '' closedBall 0 1))) (𝓝[>] 0) (𝓝 (μ (⇑A '' closedBall 0 1)))
L1 : Tendsto (fun ε ↦ μ (closedBall 0 ε + ⇑A '' closedBall 0 1)) (𝓝[>] 0) (𝓝 (μ (⇑A '' closedBall 0 1)))
⊢ d * μ (closedBall 0 1) = μ (⇑A '' closedBall 0 1)

Tactic:
exact (addHaar_image_continuousLinearMap _ _ _).symm

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

Goal state before:
pp: s : Set ℝ
f f' : ℝ → ℝ
hs : MeasurableSet s
hf' : ∀ x ∈ s, HasDerivWithinAt f (f' x) s x
hf : AntitoneOn f s
u : ℝ → ℝ≥0∞
⊢ ∫⁻ (x : ℝ) in f '' s, u x = ∫⁻ (x : ℝ) in s, ENNReal.ofReal (-f' x) * u (f x)

Tactic:
let n : ℝ → ℝ := (fun x ↦ -x)
  let e := n ∘ f
  have hg' (x) (hx : x ∈ s) : HasDerivWithinAt e (-f' x) s x := (hf' x hx).neg
  have A : ∫⁻ x in e '' s, u (n x) = ∫⁻ x in s, ENNReal.ofReal (-f' x) * (u ∘ n) (e x) := by
    rw [← lintegral_image_eq_lintegral_deriv_mul_of_monotoneOn hs hg' hf.neg (u ∘ n)]; rfl
  have B : ∫⁻ x in n '' e '' s, u x = ∫⁻ x in e '' s, ENNReal.ofReal (|-1|) * u (n x) :=
    lintegral_image_eq_lintegral_abs_deriv_mul (hs.image_of_monotoneOn hf.neg)
      (fun x hx ↦ hasDerivWithinAt_neg _ _) neg_injective.injOn _
  simp only [abs_neg, abs_one, ENNReal.ofReal_one, one_mul] at B
  rw [A, ← image_comp] at B
  convert! B using 4 with x hx x <;> simp [n, e]

Goal state after:
Module: Mathlib.Analysis.Calculus.LineDeriv.Measurable

Goal state before:
pp: 𝕜 : Type u_1
inst✝⁹ : NontriviallyNormedField 𝕜
inst✝⁸ : LocallyCompactSpace 𝕜
E : Type u_2
inst✝⁷ : NormedAddCommGroup E
inst✝⁶ : NormedSpace 𝕜 E
inst✝⁵ : MeasurableSpace E
inst✝⁴ : OpensMeasurableSpace E
F : Type u_3
inst✝³ : NormedAddCommGroup F
inst✝² : NormedSpace 𝕜 F
inst✝¹ : CompleteSpace F
f : E → F
inst✝ : SecondCountableTopology E
hf : Continuous f
⊢ StronglyMeasurable fun p ↦ lineDeriv 𝕜 f p.1 p.2

Tactic:
by
  borelize 𝕜
  let g : (E × E) → 𝕜 → F := fun p t ↦ f (p.1 + t • p.2)
  have : Continuous g.uncurry :=
    hf.comp <| (continuous_fst.comp continuous_fst).add
    <| continuous_snd.smul (continuous_snd.comp continuous_fst)
  exact (stronglyMeasurable_deriv_with_param this).comp_measurable measurable_prodMk_right

Goal state after:
Module: Mathlib.Analysis.Calculus.LocalExtr.Polynomial

Goal state before:
pp: case inr
p : ℝ[X]
hp' : derivative p ≠ 0
hp : p ≠ 0
x : ℝ
hx : x ∈ p.roots.toFinset
y : ℝ
hy : y ∈ p.roots.toFinset
hxy : x < y
hxy' : ∀ z ∈ p.roots.toFinset, z ∉ Set.Ioo x y
⊢ ∃ z ∈ (derivative p).roots.toFinset, x < z ∧ z < y

Tactic:
Multiset.mem_toFinset,

Goal state after:
case inr
p : ℝ[X]
hp' : derivative p ≠ 0
hp : p ≠ 0
x : ℝ
hx : x ∈ p.roots
y : ℝ
hy : y ∈ p.roots
hxy : x < y
hxy' : ∀ z ∈ p.roots.toFinset, z ∉ Set.Ioo x y
⊢ ∃ z ∈ (derivative p).roots.toFinset, x < z ∧ z < y
Module: Mathlib.Analysis.Calculus.LocalExtr.Polynomial

Goal state before:
pp: case inr
p : ℝ[X]
hp' : derivative p ≠ 0
hp : p ≠ 0
x : ℝ
hx : p.IsRoot x
y : ℝ
hy : p.IsRoot y
hxy : x < y
hxy' : ∀ z ∈ p.roots.toFinset, z ∉ Set.Ioo x y
z : ℝ
hz1 : z ∈ Set.Ioo x y
hz2 : deriv (fun x ↦ eval x p) z = 0
⊢ z ∈ (derivative p).roots.toFinset

Tactic:
Multiset.mem_toFinset,

Goal state after:
case inr
p : ℝ[X]
hp' : derivative p ≠ 0
hp : p ≠ 0
x : ℝ
hx : p.IsRoot x
y : ℝ
hy : p.IsRoot y
hxy : x < y
hxy' : ∀ z ∈ p.roots.toFinset, z ∉ Set.Ioo x y
z : ℝ
hz1 : z ∈ Set.Ioo x y
hz2 : deriv (fun x ↦ eval x p) z = 0
⊢ z ∈ (derivative p).roots
Module: Mathlib.MeasureTheory.Integral.IntegralEqImproper

Goal state before:
pp: E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℝ E
g : ℝ → E
a b : ℝ
hb : 0 < b
this : ∀ (c : ℝ), MeasurableSet (Ioi c)
⊢ ∫ (x : ℝ) in Ioi a, g (b * x) = b⁻¹ • ∫ (x : ℝ) in Ioi (b * a), g x

Tactic:
← integral_indicator (this _),

Goal state after:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℝ E
g : ℝ → E
a b : ℝ
hb : 0 < b
this : ∀ (c : ℝ), MeasurableSet (Ioi c)
⊢ ∫ (x : ℝ), (Ioi a).indicator (fun x ↦ g (b * x)) x ∂volume = b⁻¹ • ∫ (x : ℝ) in Ioi (b * a), g x
Module: Mathlib.MeasureTheory.Integral.IntegralEqImproper

Goal state before:
pp: E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℝ E
g : ℝ → E
a b : ℝ
hb : 0 < b
this : ∀ (c : ℝ), MeasurableSet (Ioi c)
⊢ ∫ (x : ℝ), (Ioi a).indicator (fun x ↦ g (b * x)) x ∂volume = b⁻¹ • ∫ (x : ℝ) in Ioi (b * a), g x

Tactic:
← integral_indicator (this _),

Goal state after:
E : Type u_1
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℝ E
g : ℝ → E
a b : ℝ
hb : 0 < b
this : ∀ (c : ℝ), MeasurableSet (Ioi c)
⊢ ∫ (x : ℝ), (Ioi a).indicator (fun x ↦ g (b * x)) x ∂volume = b⁻¹ • ∫ (x : ℝ), (Ioi (b * a)).indicator g x ∂volume
Module: Mathlib.Topology.Algebra.InfiniteSum.UniformOn

Goal state before:
pp: α : Type u_1
β : Type u_2
inst✝² : CommMonoid α
g : β → α
s : Set β
inst✝¹ : UniformSpace α
inst✝ : TopologicalSpace β
f : ℕ → β → α
h : TendstoLocallyUniformlyOn (fun x1 x2 ↦ ∏ i ∈ x1, f i x2) g atTop s
v : Set (α × α)
hv : v ∈ uniformity α
r : β
hr : r ∈ s
t : Set β
ht : t ∈ 𝓝[s] r
htr : ∀ᶠ (n : Finset ℕ) in atTop, ∀ y ∈ t, (g y, (fun x1 x2 ↦ ∏ i ∈ x1, f i x2) n y) ∈ v
⊢ ∃ t ∈ 𝓝[s] r, ∀ᶠ (n : ℕ) in atTop, ∀ y ∈ t, (g y, (fun N b ↦ ∏ i ∈ Finset.range N, f i b) n y) ∈ v

Tactic:
exact ⟨t, ht, Filter.tendsto_finset_range.eventually htr⟩

Goal state after:
Module: Mathlib.Geometry.Manifold.HasGroupoid

Goal state before:
pp: H : Type u
inst✝ : TopologicalSpace H
G : StructureGroupoid H
f : OpenPartialHomeomorph H H
hf : f ∈ G
⊢ f ∈ maximalAtlas H G

Tactic:
by
  rintro e (rfl : e = OpenPartialHomeomorph.refl H)
  exact ⟨G.trans (G.symm hf) G.id_mem, G.trans (G.symm G.id_mem) hf⟩

Goal state after:
Module: Mathlib.Geometry.Manifold.LocalInvariantProperties

Goal state before:
pp: case h
H : Type u_1
M : Type u_2
H' : Type u_3
inst✝³ : TopologicalSpace H
inst✝² : TopologicalSpace M
inst✝¹ : ChartedSpace H M
inst✝ : TopologicalSpace H'
G : StructureGroupoid H
G' : StructureGroupoid H'
e : OpenPartialHomeomorph M H
P : (H → H') → Set H → H → Prop
s : Set M
x : M
hG : G.LocalInvariantProp G' P
g : M → H'
he : e ∈ maximalAtlas M G
xe : x ∈ e.source
y : H
hy : ↑(chartAt H x).symm (↑(chartAt H x) (↑e.symm y)) = ↑e.symm y
⊢ ((g ∘ ↑(chartAt H x).symm) ∘ ↑((chartAt H x).symm ≫ₕ e).symm) y = (g ∘ ↑e.symm) y

Tactic:
simp [hy]

Goal state after:
Module: Mathlib.Geometry.Manifold.LocalInvariantProperties

Goal state before:
pp: case mpr.refine_1
H : Type u_1
inst✝¹ : TopologicalSpace H
G : StructureGroupoid H
inst✝ : ClosedUnderRestriction G
s : Set H
x : H
u : Set H
f : H → H
hu : IsOpen[inst✝¹] u
hux : x ∈ u
h : G.IsLocalStructomorphWithinAt f (s ∩ u) x
hx : x ∈ s
e : OpenPartialHomeomorph H H
heG : e ∈ G
hef : EqOn f (↑e.toPartialEquiv) (s ∩ u ∩ e.source)
hex : x ∈ e.source
⊢ e.restr (interior u) ∈ G

pp: case mpr.refine_2
H : Type u_1
inst✝¹ : TopologicalSpace H
G : StructureGroupoid H
inst✝ : ClosedUnderRestriction G
s : Set H
x : H
u : Set H
f : H → H
hu : IsOpen[inst✝¹] u
hux : x ∈ u
h : G.IsLocalStructomorphWithinAt f (s ∩ u) x
hx : x ∈ s
e : OpenPartialHomeomorph H H
heG : e ∈ G
hef : EqOn f (↑e.toPartialEquiv) (s ∩ u ∩ e.source)
hex : x ∈ e.source
⊢ EqOn f (↑(e.restr (interior u)).toPartialEquiv) (s ∩ (e.restr (interior u)).source)

pp: case mpr.refine_3
H : Type u_1
inst✝¹ : TopologicalSpace H
G : StructureGroupoid H
inst✝ : ClosedUnderRestriction G
s : Set H
x : H
u : Set H
f : H → H
hu : IsOpen[inst✝¹] u
hux : x ∈ u
h : G.IsLocalStructomorphWithinAt f (s ∩ u) x
hx : x ∈ s
e : OpenPartialHomeomorph H H
heG : e ∈ G
hef : EqOn f (↑e.toPartialEquiv) (s ∩ u ∩ e.source)
hex : x ∈ e.source
⊢ x ∈ (e.restr (interior u)).source

Tactic:
· exact closedUnderRestriction' heG isOpen_interior

Goal state after:
case mpr.refine_2
H : Type u_1
inst✝¹ : TopologicalSpace H
G : StructureGroupoid H
inst✝ : ClosedUnderRestriction G
s : Set H
x : H
u : Set H
f : H → H
hu : IsOpen[inst✝¹] u
hux : x ∈ u
h : G.IsLocalStructomorphWithinAt f (s ∩ u) x
hx : x ∈ s
e : OpenPartialHomeomorph H H
heG : e ∈ G
hef : EqOn f (↑e.toPartialEquiv) (s ∩ u ∩ e.source)
hex : x ∈ e.source
⊢ EqOn f (↑(e.restr (interior u)).toPartialEquiv) (s ∩ (e.restr (interior u)).source)

case mpr.refine_3
H : Type u_1
inst✝¹ : TopologicalSpace H
G : StructureGroupoid H
inst✝ : ClosedUnderRestriction G
s : Set H
x : H
u : Set H
f : H → H
hu : IsOpen[inst✝¹] u
hux : x ∈ u
h : G.IsLocalStructomorphWithinAt f (s ∩ u) x
hx : x ∈ s
e : OpenPartialHomeomorph H H
heG : e ∈ G
hef : EqOn f (↑e.toPartialEquiv) (s ∩ u ∩ e.source)
hex : x ∈ e.source
⊢ x ∈ (e.restr (interior u)).source
Module: Mathlib.Geometry.Manifold.ContMDiff.Constructions

Goal state before:
pp: 𝕜 : Type u_1
inst✝⁷ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝⁶ : NormedAddCommGroup E
inst✝⁵ : NormedSpace 𝕜 E
H : Type u_3
inst✝⁴ : TopologicalSpace H
I : ModelWithCorners 𝕜 E H
M : Type u_4
inst✝³ : TopologicalSpace M
inst✝² : ChartedSpace H M
M' : Type u_16
inst✝¹ : TopologicalSpace M'
inst✝ : ChartedSpace H M'
n : WithTop ℕ∞
⊢ ContMDiff I I n Sum.inr

Tactic:
intro x
  rw [contMDiffAt_iff]
  refine ⟨continuous_inr.continuousAt, ?_⟩
  -- In extended charts, .inl equals the identity (on the chart sources).
  apply contDiffWithinAt_id.congr_of_eventuallyEq; swap
  · simp only [mfld_simps, sum_chartAt_inr]
    congr
    apply Sum.inr_injective.extend_apply (chartAt _ x)
  set C := chartAt H x with hC
  have : I.symm ⁻¹' (chartAt H x).target ∩ range I ∈ 𝓝[range I] (extChartAt I x) x := by
    rw [← I.image_eq (chartAt H x).target]
    exact (chartAt H x).extend_image_target_mem_nhds (mem_chart_source _ x)
  filter_upwards [this] with y hy
  simp [extChartAt, sum_chartAt_inr, ← hC, Sum.inr_injective.extend_apply C, C.right_inv hy.1,
    I.right_inv hy.2]

Goal state after:
Module: Mathlib.Analysis.Normed.Operator.Prod

Goal state before:
pp: 𝕜 : Type u_1
E : Type u_2
F : Type u_3
inst✝⁴ : NontriviallyNormedField 𝕜
inst✝³ : SeminormedAddCommGroup E
inst✝² : SeminormedAddCommGroup F
inst✝¹ : NormedSpace 𝕜 E
inst✝ : NormedSpace 𝕜 F
x✝ : E × F
e : E
f : F
⊢ ‖(snd 𝕜 E F) (e, f)‖ ≤ 1 * ‖(e, f)‖

Tactic:
by simpa only [one_mul] using! le_max_right ‖e‖ ‖f‖

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

Goal state before:
pp: E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
s : Set E
f : E → E
f' : E → E →L[ℝ] E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
hs : MeasurableSet s
hf' : ∀ x ∈ s, HasFDerivWithinAt f (f' x) s x
hf : InjOn f s
u : E → E
u_meas : Measurable u
uf : EqOn u f s
u' : ∀ x ∈ s, HasFDerivWithinAt u (f' x) s x
F : ↑s → E := u ∘ Subtype.val
hF : F = u ∘ Subtype.val
A : Measure.map F (Measure.comap Subtype.val (μ.withDensity fun x ↦ ENNReal.ofReal |(f' x).det|)) = μ.restrict (f '' s)
⊢ Measure.map (s.domRestrict f) (Measure.comap Subtype.val (μ.withDensity fun x ↦ ENNReal.ofReal |(f' x).det|)) =
    μ.restrict (f '' s)

Tactic:
have : F = s.domRestrict f := by
    ext x
    exact uf x.2

Goal state after:
E : Type u_1
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace ℝ E
inst✝³ : FiniteDimensional ℝ E
s : Set E
f : E → E
f' : E → E →L[ℝ] E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
μ : Measure E
inst✝ : μ.IsAddHaarMeasure
hs : MeasurableSet s
hf' : ∀ x ∈ s, HasFDerivWithinAt f (f' x) s x
hf : InjOn f s
u : E → E
u_meas : Measurable u
uf : EqOn u f s
u' : ∀ x ∈ s, HasFDerivWithinAt u (f' x) s x
F : ↑s → E := u ∘ Subtype.val
hF : F = u ∘ Subtype.val
A : Measure.map F (Measure.comap Subtype.val (μ.withDensity fun x ↦ ENNReal.ofReal |(f' x).det|)) = μ.restrict (f '' s)
this : F = s.domRestrict f
⊢ Measure.map (s.domRestrict f) (Measure.comap Subtype.val (μ.withDensity fun x ↦ ENNReal.ofReal |(f' x).det|)) =
    μ.restrict (f '' s)
Module: Mathlib.Geometry.Manifold.MFDeriv.Defs

Goal state before:
pp: 𝕜 : Type u_1
inst✝⁶ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
H : Type u_3
inst✝³ : TopologicalSpace H
I : ModelWithCorners 𝕜 E H
E' : Type u_5
inst✝² : NormedAddCommGroup E'
inst✝¹ : NormedSpace 𝕜 E'
H' : Type u_6
inst✝ : TopologicalSpace H'
I' : ModelWithCorners 𝕜 E' H'
s : Set H
x : H
f : H → H'
e' : OpenPartialHomeomorph H' H'
he' : e' ∈ contDiffGroupoid 1 I'
hs : s ⊆ f ⁻¹' e'.source
hx : f x ∈ e'.source
h : DifferentiableWithinAt 𝕜 (↑I' ∘ f ∘ ↑I.symm) (↑I.symm ⁻¹' s ∩ range ↑I) (↑I x)
⊢ DifferentiableWithinAt 𝕜 (↑I' ∘ (↑e' ∘ f) ∘ ↑I.symm) (↑I.symm ⁻¹' s ∩ range ↑I) (↑I x)

Tactic:
have A : (I' ∘ f ∘ I.symm) (I x) ∈ I'.symm ⁻¹' e'.source ∩ Set.range I' := by
        simp only [hx, mfld_simps]

Goal state after:
𝕜 : Type u_1
inst✝⁶ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝⁵ : NormedAddCommGroup E
inst✝⁴ : NormedSpace 𝕜 E
H : Type u_3
inst✝³ : TopologicalSpace H
I : ModelWithCorners 𝕜 E H
E' : Type u_5
inst✝² : NormedAddCommGroup E'
inst✝¹ : NormedSpace 𝕜 E'
H' : Type u_6
inst✝ : TopologicalSpace H'
I' : ModelWithCorners 𝕜 E' H'
s : Set H
x : H
f : H → H'
e' : OpenPartialHomeomorph H' H'
he' : e' ∈ contDiffGroupoid 1 I'
hs : s ⊆ f ⁻¹' e'.source
hx : f x ∈ e'.source
h : DifferentiableWithinAt 𝕜 (↑I' ∘ f ∘ ↑I.symm) (↑I.symm ⁻¹' s ∩ range ↑I) (↑I x)
A : (↑I' ∘ f ∘ ↑I.symm) (↑I x) ∈ ↑I'.symm ⁻¹' e'.source ∩ range ↑I'
⊢ DifferentiableWithinAt 𝕜 (↑I' ∘ (↑e' ∘ f) ∘ ↑I.symm) (↑I.symm ⁻¹' s ∩ range ↑I) (↑I x)
Module: Mathlib.Geometry.Manifold.ContMDiff.Defs

Goal state before:
pp: 𝕜 : Type u_1
inst✝¹² : NontriviallyNormedField 𝕜
E : Type u_2
inst✝¹¹ : NormedAddCommGroup E
inst✝¹⁰ : NormedSpace 𝕜 E
H : Type u_3
inst✝⁹ : TopologicalSpace H
I : ModelWithCorners 𝕜 E H
M : Type u_4
inst✝⁸ : TopologicalSpace M
inst✝⁷ : ChartedSpace H M
E' : Type u_5
inst✝⁶ : NormedAddCommGroup E'
inst✝⁵ : NormedSpace 𝕜 E'
H' : Type u_6
inst✝⁴ : TopologicalSpace H'
I' : ModelWithCorners 𝕜 E' H'
M' : Type u_7
inst✝³ : TopologicalSpace M'
inst✝² : ChartedSpace H' M'
f : M → M'
s✝ : Set M
x : M
n : ℕ∞ω
inst✝¹ : IsManifold I n M
inst✝ : IsManifold I' n M'
hn : n ≠ ∞
s : Set M
hxs : x ∈ s
h : ContMDiffWithinAt I I' n f s x
⊢ n = ∞ → n = ω

Tactic:
by simp [hn]

Goal state after:
Module: Mathlib.Geometry.Manifold.Algebra.Monoid

Goal state before:
pp: 𝕜 : Type u_1
inst✝¹⁴ : NontriviallyNormedField 𝕜
n : ℕ∞ω
H : Type u_2
inst✝¹³ : TopologicalSpace H
E : Type u_3
inst✝¹² : NormedAddCommGroup E
inst✝¹¹ : NormedSpace 𝕜 E
I : ModelWithCorners 𝕜 E H
G : Type u_4
inst✝¹⁰ : Monoid G
inst✝⁹ : TopologicalSpace G
inst✝⁸ : ChartedSpace H G
inst✝⁷ : ContMDiffMul I n G
H' : Type u_5
inst✝⁶ : TopologicalSpace H'
E' : Type u_6
inst✝⁵ : NormedAddCommGroup E'
inst✝⁴ : NormedSpace 𝕜 E'
I' : ModelWithCorners 𝕜 E' H'
G' : Type u_7
inst✝³ : Monoid G'
inst✝² : TopologicalSpace G'
inst✝¹ : ChartedSpace H' G'
inst✝ : ContMDiffMul I' n G'
f g : ContMDiffMonoidMorphism I I' n G G'
h : (fun a ↦ (↑a.toMonoidHom).toFun) f = (fun a ↦ (↑a.toMonoidHom).toFun) g
⊢ f = g

Tactic:
by cases f; cases g; congr; exact DFunLike.ext' h

Goal state after:
Module: Mathlib.Geometry.Manifold.ContMDiff.Atlas

Goal state before:
pp: 𝕜 : Type u_1
inst✝³ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace 𝕜 E
H : Type u_3
inst✝ : TopologicalSpace H
I : ModelWithCorners 𝕜 E H
n : ℕ∞ω
x : H
y : E
hy : y ∈ range ↑I
⊢ (↑I ∘ ↑I.symm) y = id y

Tactic:
simp [hy]

Goal state after:
Module: Mathlib.Geometry.Manifold.ContMDiff.Atlas

Goal state before:
pp: 𝕜 : Type u_1
inst✝³ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝² : NormedAddCommGroup E
inst✝¹ : NormedSpace 𝕜 E
H : Type u_3
inst✝ : TopologicalSpace H
I : ModelWithCorners 𝕜 E H
n : ℕ∞ω
x : E
hx : x ∈ range ↑I
y : E
hy : y ∈ range ↑I
⊢ (↑I ∘ ↑I.symm) y = id y

Tactic:
simp [hy]

Goal state after:
Module: Mathlib.Geometry.Manifold.MFDeriv.Basic

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
s : Set M
x : M
⊢ 𝓝[↑(extChartAt I x).symm ⁻¹' s] ↑(extChartAt I x) x ⊓ 𝓝[range ↑I] ↑(extChartAt I x) x =
    𝓝[↑(extChartAt I x).symm ⁻¹' s] ↑(extChartAt I x) x ⊓ 𝓝[(extChartAt I x).target] ↑(extChartAt I x) x

Tactic:
nhdsWithin_extChartAt_target_eq

Goal state after:
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
s : Set M
x : M
⊢ 𝓝[↑(extChartAt I x).symm ⁻¹' s] ↑(extChartAt I x) x ⊓ 𝓝[range ↑I] ↑(extChartAt I x) x =
    𝓝[↑(extChartAt I x).symm ⁻¹' s] ↑(extChartAt I x) x ⊓ 𝓝[range ↑I] ↑(extChartAt I x) x
Module: Mathlib.Geometry.Manifold.MFDeriv.Basic

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
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 : M → M'
x : M
h : ¬MDiffAt f x
⊢ mfderiv% f x = 0

Tactic:
by simp only [mfderiv, h, if_neg, not_false_iff]

Goal state after:
Module: Mathlib.Geometry.Manifold.VectorBundle.FiberwiseLinear

Goal state before:
pp: 𝕜 : Type u_1
B : Type u_2
F : Type u_3
inst✝⁷ : TopologicalSpace B
inst✝⁶ : NontriviallyNormedField 𝕜
inst✝⁵ : NormedAddCommGroup F
inst✝⁴ : NormedSpace 𝕜 F
EB : Type u_4
inst✝³ : NormedAddCommGroup EB
inst✝² : NormedSpace 𝕜 EB
HB : Type u_5
inst✝¹ : TopologicalSpace HB
inst✝ : ChartedSpace HB B
IB : ModelWithCorners 𝕜 EB HB
n : ℕ∞ω
e : OpenPartialHomeomorph (B × F) (B × F)
φ : B → F ≃L[𝕜] F
U : Set B
hU : IsOpen[inst✝⁷] U
hφ : ContMDiffOn IB 𝓘(𝕜, F →L[𝕜] F) n (fun x ↦ ↑(φ x)) U
h2φ : ContMDiffOn IB 𝓘(𝕜, F →L[𝕜] F) n (fun x ↦ ↑(φ x).symm) U
heφ : e.EqOnSource (FiberwiseLinear.openPartialHomeomorph φ hU ⋯ ⋯)
⊢ ContMDiffOn IB 𝓘(𝕜, F →L[𝕜] F) n (fun x ↦ ↑(φ x)) U

Tactic:
exact hφ

Goal state after: