mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.GroupTheory.HNNExtension

Goal state before:
pp: case pos
G : Type u_1
inst✝ : Group G
A B : Subgroup G
φ : ↥A ≃* ↥B
d : TransversalPair G A B
w : ReducedWord G A B
this :
  ∀ (w : ReducedWord G A B),
    w.head = 1 →
      ∃ w',
        ReducedWord.prod φ w'.toReducedWord = ReducedWord.prod φ w ∧
          List.map Prod.fst w'.toList = List.map Prod.fst w.toList ∧
            ∀ u ∈ Option.map Prod.fst w.toList.head?, w'.head ∈ toSubgroup A B (-u)
hw1 : w.head = 1
⊢ ∃ w',
    ReducedWord.prod φ w'.toReducedWord = ReducedWord.prod φ w ∧
      List.map Prod.fst w'.toList = List.map Prod.fst w.toList ∧
        ∀ u ∈ Option.map Prod.fst w.toList.head?, w'.head⁻¹ * w.head ∈ toSubgroup A B (-u)

pp: case neg
G : Type u_1
inst✝ : Group G
A B : Subgroup G
φ : ↥A ≃* ↥B
d : TransversalPair G A B
w : ReducedWord G A B
this :
  ∀ (w : ReducedWord G A B),
    w.head = 1 →
      ∃ w',
        ReducedWord.prod φ w'.toReducedWord = ReducedWord.prod φ w ∧
          List.map Prod.fst w'.toList = List.map Prod.fst w.toList ∧
            ∀ u ∈ Option.map Prod.fst w.toList.head?, w'.head ∈ toSubgroup A B (-u)
hw1 : ¬w.head = 1
⊢ ∃ w',
    ReducedWord.prod φ w'.toReducedWord = ReducedWord.prod φ w ∧
      List.map Prod.fst w'.toList = List.map Prod.fst w.toList ∧
        ∀ u ∈ Option.map Prod.fst w.toList.head?, w'.head⁻¹ * w.head ∈ toSubgroup A B (-u)

Tactic:
· simp only [hw1, inv_mem_iff, mul_one]
      exact this w hw1

Goal state after:
case neg
G : Type u_1
inst✝ : Group G
A B : Subgroup G
φ : ↥A ≃* ↥B
d : TransversalPair G A B
w : ReducedWord G A B
this :
  ∀ (w : ReducedWord G A B),
    w.head = 1 →
      ∃ w',
        ReducedWord.prod φ w'.toReducedWord = ReducedWord.prod φ w ∧
          List.map Prod.fst w'.toList = List.map Prod.fst w.toList ∧
            ∀ u ∈ Option.map Prod.fst w.toList.head?, w'.head ∈ toSubgroup A B (-u)
hw1 : ¬w.head = 1
⊢ ∃ w',
    ReducedWord.prod φ w'.toReducedWord = ReducedWord.prod φ w ∧
      List.map Prod.fst w'.toList = List.map Prod.fst w.toList ∧
        ∀ u ∈ Option.map Prod.fst w.toList.head?, w'.head⁻¹ * w.head ∈ toSubgroup A B (-u)
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a : g.Basis
τ : ↥(range_toPermHom' g)
x : α
c : ↥g.cycleFactorsFinset
hx : x ∈ (↑c).support
m : ℤ
hm : (g ^ m) (a c) = x
hx' : ↑c = g.cycleOf x
hx'' : g.cycleOf x ∈ g.cycleFactorsFinset
n : ℕ := Nat.find ⋯
⊢ (g ^ ↑n) (a c) = x

Tactic:
rw [← Nat.find_spec (a.sameCycle hx'').exists_nat_pow_eq, zpow_natCast]

Goal state after:
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a : g.Basis
τ : ↥(range_toPermHom' g)
x : α
c : ↥g.cycleFactorsFinset
hx : x ∈ (↑c).support
m : ℤ
hm : (g ^ m) (a c) = x
hx' : ↑c = g.cycleOf x
hx'' : g.cycleOf x ∈ g.cycleFactorsFinset
n : ℕ := Nat.find ⋯
⊢ (g ^ n) (a c) = (g ^ Nat.find ⋯) (a ⟨g.cycleOf x, hx''⟩)
Module: Mathlib.GroupTheory.Perm.ClosureSwap

Goal state before:
pp: case refine_1
α : Type u_2
inst✝ : DecidableEq α
S : Set (Equiv.Perm α)
hS : ∀ f ∈ S, f.IsSwap
supp : Set α
fin : supp.Finite
a : α
s : Set α
ih : ∀ {f : Equiv.Perm α}, (∀ (x : α), f x ∈ orbit (↥(closure S)) x) → (fixedBy α f)ᶜ ⊆ s → f ∈ closure S
f : Equiv.Perm α
hf : ∀ (x : α), f x ∈ orbit (↥(closure S)) x
supp_subset : (fixedBy α f)ᶜ ⊆ insert a s
b : α
⊢ (Equiv.swap (f a) a * f) b ∈ orbit (↥(closure S)) b

Tactic:
rw [Perm.mul_apply, swap_apply_def]

Goal state after:
case refine_1
α : Type u_2
inst✝ : DecidableEq α
S : Set (Equiv.Perm α)
hS : ∀ f ∈ S, f.IsSwap
supp : Set α
fin : supp.Finite
a : α
s : Set α
ih : ∀ {f : Equiv.Perm α}, (∀ (x : α), f x ∈ orbit (↥(closure S)) x) → (fixedBy α f)ᶜ ⊆ s → f ∈ closure S
f : Equiv.Perm α
hf : ∀ (x : α), f x ∈ orbit (↥(closure S)) x
supp_subset : (fixedBy α f)ᶜ ⊆ insert a s
b : α
⊢ (if f b = f a then a else if f b = a then f a else f b) ∈ orbit (↥(closure S)) b
Module: Mathlib.GroupTheory.HNNExtension

Goal state before:
pp: G : Type u_1
inst✝ : Group G
A B : Subgroup G
φ : ↥A ≃* ↥B
w₁ w₂ : ReducedWord G A B
hprod : ReducedWord.prod φ w₁ = ReducedWord.prod φ w₂
d : TransversalPair G A B
w₁' : NormalWord d
hw₁'1 : ReducedWord.prod φ w₁'.toReducedWord = ReducedWord.prod φ w₁
hw₁'2 : List.map Prod.fst w₁'.toList = List.map Prod.fst w₁.toList
hw₂'1 : ReducedWord.prod φ w₁'.toReducedWord = ReducedWord.prod φ w₂
hw₂'2 : List.map Prod.fst w₁'.toList = List.map Prod.fst w₂.toList
hw₁'3 : ∀ u ∈ Option.map Prod.fst w₁.toList.head?, w₁'.head • ↑(toSubgroup A B (-u)) = w₁.head • ↑(toSubgroup A B (-u))
hw₂'3 : ∀ u ∈ Option.map Prod.fst w₂.toList.head?, w₁'.head • ↑(toSubgroup A B (-u)) = w₂.head • ↑(toSubgroup A B (-u))
u : ℤˣ
hu : u ∈ Option.map Prod.fst w₁.toList.head?
⊢ w₁.head • ↑(toSubgroup A B (-u)) = w₂.head • ↑(toSubgroup A B (-u))

Tactic:
← hw₁'3 _ hu,

Goal state after:
G : Type u_1
inst✝ : Group G
A B : Subgroup G
φ : ↥A ≃* ↥B
w₁ w₂ : ReducedWord G A B
hprod : ReducedWord.prod φ w₁ = ReducedWord.prod φ w₂
d : TransversalPair G A B
w₁' : NormalWord d
hw₁'1 : ReducedWord.prod φ w₁'.toReducedWord = ReducedWord.prod φ w₁
hw₁'2 : List.map Prod.fst w₁'.toList = List.map Prod.fst w₁.toList
hw₂'1 : ReducedWord.prod φ w₁'.toReducedWord = ReducedWord.prod φ w₂
hw₂'2 : List.map Prod.fst w₁'.toList = List.map Prod.fst w₂.toList
hw₁'3 : ∀ u ∈ Option.map Prod.fst w₁.toList.head?, w₁'.head • ↑(toSubgroup A B (-u)) = w₁.head • ↑(toSubgroup A B (-u))
hw₂'3 : ∀ u ∈ Option.map Prod.fst w₂.toList.head?, w₁'.head • ↑(toSubgroup A B (-u)) = w₂.head • ↑(toSubgroup A B (-u))
u : ℤˣ
hu : u ∈ Option.map Prod.fst w₁.toList.head?
⊢ w₁'.head • ↑(toSubgroup A B (-u)) = w₂.head • ↑(toSubgroup A B (-u))
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: case refine_1.hind
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a : ↥g.cycleFactorsFinset
⊢ ∀ a_1 ∈ {↑a}, ∀ b ∈ ⋃ i, ⋃ (_ : ¬i = a), {↑i}, _root_.Disjoint a_1.support b.support

Tactic:
rintro - ⟨-⟩ - ⟨-, ⟨b, rfl⟩, -, ⟨h, rfl⟩, ⟨-⟩⟩

Goal state after:
case refine_1.hind
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
g : Perm α
a b : ↥g.cycleFactorsFinset
h : ¬b = a
⊢ _root_.Disjoint (↑a).support (↑b).support
Module: Mathlib.GroupTheory.SpecificGroups.Alternating.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
n : ℕ
hn : 2 ≤ n
hα : n ≤ Fintype.card α
⊢ (if Even (n + 1) then #{g | g.cycleType = {n}} else 0) = if Odd n then (n - 1)! * (Fintype.card α).choose n else 0

Tactic:
← Nat.not_odd_iff_even,

Goal state after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
n : ℕ
hn : 2 ≤ n
hα : n ≤ Fintype.card α
⊢ (if ¬Odd (n + 1) then #{g | g.cycleType = {n}} else 0) = if Odd n then (n - 1)! * (Fintype.card α).choose n else 0
Module: Mathlib.GroupTheory.SchurZassenhaus

Goal state before:
pp: case refine_1
G : Type u
inst✝³ : Group G
N : Subgroup G
inst✝² : N.Normal
h1 : (Nat.card ↥N).Coprime N.index
h2 :
  ∀ (G' : Type u) [inst : Group G'] [Finite G'],
    Nat.card G' < Nat.card G →
      ∀ {N' : Subgroup G'} [N'.Normal], (Nat.card ↥N').Coprime N'.index → ∃ H', N'.IsComplement' H'
h3 : ∀ (H : Subgroup G), ¬N.IsComplement' H
inst✝¹ : Finite G
K : Subgroup G
inst✝ : K.Normal
hK : K ≤ N
this : Function.Surjective ⇑(QuotientGroup.mk' K)
h4 : K ≠ ⊥ ∧ K ≠ N
h5 : Nat.card (G ⧸ K) < Nat.card G
h6 : (Nat.card ↥(map (QuotientGroup.mk' K) N)).Coprime (map (QuotientGroup.mk' K) N).index
H : Subgroup (G ⧸ K)
hH : (map (QuotientGroup.mk' K) N).IsComplement' H
key : comap (QuotientGroup.mk' K) (map (QuotientGroup.mk' K) N) = N
⊢ comap (QuotientGroup.mk' K) H ⊔ comap (QuotientGroup.mk' K) (map (QuotientGroup.mk' K) N) = ⊤

Tactic:
comap_sup_eq,

Goal state after:
case refine_1
G : Type u
inst✝³ : Group G
N : Subgroup G
inst✝² : N.Normal
h1 : (Nat.card ↥N).Coprime N.index
h2 :
  ∀ (G' : Type u) [inst : Group G'] [Finite G'],
    Nat.card G' < Nat.card G →
      ∀ {N' : Subgroup G'} [N'.Normal], (Nat.card ↥N').Coprime N'.index → ∃ H', N'.IsComplement' H'
h3 : ∀ (H : Subgroup G), ¬N.IsComplement' H
inst✝¹ : Finite G
K : Subgroup G
inst✝ : K.Normal
hK : K ≤ N
this : Function.Surjective ⇑(QuotientGroup.mk' K)
h4 : K ≠ ⊥ ∧ K ≠ N
h5 : Nat.card (G ⧸ K) < Nat.card G
h6 : (Nat.card ↥(map (QuotientGroup.mk' K) N)).Coprime (map (QuotientGroup.mk' K) N).index
H : Subgroup (G ⧸ K)
hH : (map (QuotientGroup.mk' K) N).IsComplement' H
key : comap (QuotientGroup.mk' K) (map (QuotientGroup.mk' K) N) = N
⊢ comap (QuotientGroup.mk' K) (H ⊔ map (QuotientGroup.mk' K) N) = ⊤

case refine_1.hf
G : Type u
inst✝³ : Group G
N : Subgroup G
inst✝² : N.Normal
h1 : (Nat.card ↥N).Coprime N.index
h2 :
  ∀ (G' : Type u) [inst : Group G'] [Finite G'],
    Nat.card G' < Nat.card G →
      ∀ {N' : Subgroup G'} [N'.Normal], (Nat.card ↥N').Coprime N'.index → ∃ H', N'.IsComplement' H'
h3 : ∀ (H : Subgroup G), ¬N.IsComplement' H
inst✝¹ : Finite G
K : Subgroup G
inst✝ : K.Normal
hK : K ≤ N
this : Function.Surjective ⇑(QuotientGroup.mk' K)
h4 : K ≠ ⊥ ∧ K ≠ N
h5 : Nat.card (G ⧸ K) < Nat.card G
h6 : (Nat.card ↥(map (QuotientGroup.mk' K) N)).Coprime (map (QuotientGroup.mk' K) N).index
H : Subgroup (G ⧸ K)
hH : (map (QuotientGroup.mk' K) N).IsComplement' H
key : comap (QuotientGroup.mk' K) (map (QuotientGroup.mk' K) N) = N
⊢ Function.Surjective ⇑(QuotientGroup.mk' K)
Module: Mathlib.GroupTheory.SchurZassenhaus

Goal state before:
pp: case refine_1
G : Type u
inst✝³ : Group G
N : Subgroup G
inst✝² : N.Normal
h1 : (Nat.card ↥N).Coprime N.index
h2 :
  ∀ (G' : Type u) [inst : Group G'] [Finite G'],
    Nat.card G' < Nat.card G →
      ∀ {N' : Subgroup G'} [N'.Normal], (Nat.card ↥N').Coprime N'.index → ∃ H', N'.IsComplement' H'
h3 : ∀ (H : Subgroup G), ¬N.IsComplement' H
inst✝¹ : Finite G
K : Subgroup G
inst✝ : K.Normal
hK : K ≤ N
this : Function.Surjective ⇑(QuotientGroup.mk' K)
h4 : K ≠ ⊥ ∧ K ≠ N
h5 : Nat.card (G ⧸ K) < Nat.card G
h6 : (Nat.card ↥(map (QuotientGroup.mk' K) N)).Coprime (map (QuotientGroup.mk' K) N).index
H : Subgroup (G ⧸ K)
hH : (map (QuotientGroup.mk' K) N).IsComplement' H
⊢ comap (QuotientGroup.mk' K) H ⊔ N = ⊤

Tactic:
have key : (N.map (QuotientGroup.mk' K)).comap (QuotientGroup.mk' K) = N := by
      refine comap_map_eq_self ?_
      rwa [QuotientGroup.ker_mk']
    rwa [← key, comap_sup_eq, hH.symm.sup_eq_top, comap_top]

Goal state after:
Module: Mathlib.GroupTheory.Perm.Centralizer

Goal state before:
pp: case pos
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
hm : m.sum ≤ Fintype.card α ∧ ∀ a ∈ m, 2 ≤ a
⊢ #{g | g.cycleType = m} =
    (Fintype.card α)! / ((Fintype.card α - m.sum)! * m.prod * ∏ n ∈ m.toFinset, (Multiset.count n m)!)

Tactic:
apply symm

Goal state after:
case pos
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
m : Multiset ℕ
hm : m.sum ≤ Fintype.card α ∧ ∀ a ∈ m, 2 ≤ a
⊢ (Fintype.card α)! / ((Fintype.card α - m.sum)! * m.prod * ∏ n ∈ m.toFinset, (Multiset.count n m)!) =
    #{g | g.cycleType = m}
Module: Mathlib.GroupTheory.SchurZassenhaus

Goal state before:
pp: G : Type u
inst✝³ : Group G
N : Subgroup G
inst✝² : N.Normal
h1 : (Nat.card ↥N).Coprime N.index
h2 :
  ∀ (G' : Type u) [inst : Group G'] [Finite G'],
    Nat.card G' < Nat.card G →
      ∀ {N' : Subgroup G'} [N'.Normal], (Nat.card ↥N').Coprime N'.index → ∃ H', N'.IsComplement' H'
h3 : ∀ (H : Subgroup G), ¬N.IsComplement' H
inst✝¹ : Finite G
K : Subgroup ↥N
inst✝ : (map N.subtype K).Normal
key : map N.subtype K = ⊥ ∨ map N.subtype K = N
⊢ K = ⊥ ∨ K = ⊤

Tactic:
← map_bot N.subtype

Goal state after:
G : Type u
inst✝³ : Group G
N : Subgroup G
inst✝² : N.Normal
h1 : (Nat.card ↥N).Coprime N.index
h2 :
  ∀ (G' : Type u) [inst : Group G'] [Finite G'],
    Nat.card G' < Nat.card G →
      ∀ {N' : Subgroup G'} [N'.Normal], (Nat.card ↥N').Coprime N'.index → ∃ H', N'.IsComplement' H'
h3 : ∀ (H : Subgroup G), ¬N.IsComplement' H
inst✝¹ : Finite G
K : Subgroup ↥N
inst✝ : (map N.subtype K).Normal
key : map N.subtype K = map N.subtype ⊥ ∨ map N.subtype K = N
⊢ K = ⊥ ∨ K = ⊤
Module: Mathlib.GroupTheory.SpecificGroups.Alternating.KleinFour

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
hα4 : Nat.card α = 4
S : Sylow 2 ↥(alternatingGroup α)
⊢ ↑S = Subgroup.closure ({1} ∪ {g | (↑g).cycleType = {2, 2}})

Tactic:
← coe_two_sylow_of_card_eq_four hα4

Goal state after:
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
hα4 : Nat.card α = 4
S : Sylow 2 ↥(alternatingGroup α)
⊢ ↑S = Subgroup.closure ↑?m.28

α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
hα4 : Nat.card α = 4
S : Sylow 2 ↥(alternatingGroup α)
⊢ Sylow 2 ↥(alternatingGroup α)
Module: Mathlib.GroupTheory.SpecificGroups.Alternating.Centralizer

Goal state before:
pp: α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
h5 : 5 ≤ Nat.card α
this : closure {b | (↑b).IsThreeCycle} = ⊤
b : ↥(alternatingGroup α)
⊢ b ∈ {b | (↑b).IsThreeCycle} → b ∈ ↑(_root_.commutator ↥(alternatingGroup α))

Tactic:
hb

Goal state after:
α : Type u_1
inst✝¹ : Fintype α
inst✝ : DecidableEq α
h5 : 5 ≤ Nat.card α
this : closure {b | (↑b).IsThreeCycle} = ⊤
b : ↥(alternatingGroup α)
hb : b ∈ {b | (↑b).IsThreeCycle}
⊢ b ∈ ↑(_root_.commutator ↥(alternatingGroup α))
Module: Mathlib.GroupTheory.SpecificGroups.Quaternion

Goal state before:
pp: n : ℕ
i : ZMod (2 * n)
⊢ xa i ^ 2 = a ↑n

Tactic:
simp [sq]

Goal state after:
Module: Mathlib.GroupTheory.SpecificGroups.Quaternion

Goal state before:
pp: n : ℕ
⊢ Monoid.exponent (QuaternionGroup n) = 2 * lcm n 2

Tactic:
rw [← normalize_eq 2, ← lcm_mul_left, normalize_eq]

Goal state after:
n : ℕ
⊢ Monoid.exponent (QuaternionGroup n) = lcm (2 * n) (2 * 2)
Module: Mathlib.GroupTheory.SpecificGroups.Alternating.Simple

Goal state before:
pp: α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
hα : 5 ≤ Nat.card α
⊢ ∃ x y, x ≠ y

Tactic:
rw [← _root_.nontrivial_iff]

Goal state after:
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
hα : 5 ≤ Nat.card α
⊢ Nontrivial ↥(alternatingGroup α)
Module: Mathlib.GroupTheory.SpecificGroups.ZGroup

Goal state before:
pp: case refine_2
G : Type u_1
inst✝³ : Group G
p : ℕ
inst✝² : Fact (Nat.Prime p)
inst✝¹ : Finite G
P : Sylow p G
inst✝ : IsCyclic ↥↑P
hP : ↑P ≤ commutator G
h : p ∣ (commutator G).index
⊢ (commutator G).index ∣ (↑P).index

Tactic:
· exact Subgroup.index_dvd_of_le hP

Goal state after:
Module: Mathlib.Probability.Kernel.Defs

Goal state before:
pp: case insert
α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
κs : ι → Kernel α β
i : ι
I : Finset ι
hi_notMem_I : i ∉ I
h_ind : (∀ i ∈ I, IsSFiniteKernel (κs i)) → IsSFiniteKernel (∑ i ∈ I, κs i)
h : ∀ i_1 ∈ insert i I, IsSFiniteKernel (κs i_1)
⊢ IsSFiniteKernel (κs i + ∑ x ∈ I, κs x)

Tactic:
have : IsSFiniteKernel (κs i) := h i (Finset.mem_insert_self _ _)

Goal state after:
case insert
α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
κs : ι → Kernel α β
i : ι
I : Finset ι
hi_notMem_I : i ∉ I
h_ind : (∀ i ∈ I, IsSFiniteKernel (κs i)) → IsSFiniteKernel (∑ i ∈ I, κs i)
h : ∀ i_1 ∈ insert i I, IsSFiniteKernel (κs i_1)
this : IsSFiniteKernel (κs i)
⊢ IsSFiniteKernel (κs i + ∑ x ∈ I, κs x)
Module: Mathlib.Probability.Kernel.Composition.Comp

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
κ : Kernel α β
η : Kernel β γ
s : Set γ
a : α
hs : ((η ∘ₖ κ) a) s ≠ ∞
h : ∀ᵐ (b : β) ∂κ a, (η b) (toMeasurable ((η ∘ₖ κ) a) s) < ∞
b : β
⊢ (η b) (toMeasurable ((η ∘ₖ κ) a) s) < ∞ → (η b) s < ∞

Tactic:
hb

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
κ : Kernel α β
η : Kernel β γ
s : Set γ
a : α
hs : ((η ∘ₖ κ) a) s ≠ ∞
h : ∀ᵐ (b : β) ∂κ a, (η b) (toMeasurable ((η ∘ₖ κ) a) s) < ∞
b : β
hb : (η b) (toMeasurable ((η ∘ₖ κ) a) s) < ∞
⊢ (η b) s < ∞
Module: Mathlib.Probability.Kernel.Composition.Comp

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
κ : Kernel α β
η : Kernel β γ
s : Set γ
a : α
hs : MeasurableSet s
⊢ ∫⁻ (b : β), (η b) s ∂κ a = 0 ↔ (fun y ↦ (η y) s) =ᵐ[κ a] 0

Tactic:
lintegral_eq_zero_iff (η.measurable_coe hs)

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
κ : Kernel α β
η : Kernel β γ
s : Set γ
a : α
hs : MeasurableSet s
⊢ (fun a ↦ (η a) s) =ᵐ[κ a] 0 ↔ (fun y ↦ (η y) s) =ᵐ[κ a] 0
Module: Mathlib.Probability.Kernel.Composition.Comp

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
κ : Kernel α β
η : Kernel β γ
a : α
s : Set γ
h : ((η ∘ₖ κ) a) s = 0
⊢ (fun x ↦ (η x) s) =ᵐ[κ a] 0

Tactic:
obtain ⟨t, hst, mt, ht⟩ := exists_measurable_superset_of_null h
  simp_rw [comp_null a mt] at ht
  rw [Filter.eventuallyLE_antisymm_iff]
  exact ⟨Filter.EventuallyLE.trans_eq (ae_of_all _ fun _ ↦ measure_mono hst) ht,
    ae_of_all _ fun _ ↦ zero_le⟩

Goal state after:
Module: Mathlib.Probability.Kernel.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
κ : Kernel α β
μ : Measure α
h : ∀ᵐ (a : α) ∂μ, IsProbabilityMeasure (κ a)
h' : μ ≠ 0
s : Set α
s_meas : MeasurableSet s
μs : μ s = 0
hs : ∀ a ∉ s, IsProbabilityMeasure (κ a)
a : α
ha : a ∈ sᶜ
b : α
⊢ b ∉ s → κ b = (piecewise s_meas (const α (κ a)) κ) b

Tactic:
hb

Goal state after:
α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
κ : Kernel α β
μ : Measure α
h : ∀ᵐ (a : α) ∂μ, IsProbabilityMeasure (κ a)
h' : μ ≠ 0
s : Set α
s_meas : MeasurableSet s
μs : μ s = 0
hs : ∀ a ∉ s, IsProbabilityMeasure (κ a)
a : α
ha : a ∈ sᶜ
b : α
hb : b ∉ s
⊢ κ b = (piecewise s_meas (const α (κ a)) κ) b
Module: Mathlib.Probability.Kernel.Basic

Goal state before:
pp: α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
κ : Kernel α β
μ ν : Measure α
inst✝¹ : SFinite μ
inst✝ : SFinite ν
b : Bool
s✝ : Set α
a✝ : MeasurableSet s✝
⊢ ((boolKernel μ ν) b) s✝ = ((Kernel.sum fun n ↦ boolKernel (sfiniteSeq μ n) (sfiniteSeq ν n)) b) s✝

Tactic:
Kernel.sum_apply

Goal state after:
α : Type u_1
β : Type u_2
ι : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
κ : Kernel α β
μ ν : Measure α
inst✝¹ : SFinite μ
inst✝ : SFinite ν
b : Bool
s✝ : Set α
a✝ : MeasurableSet s✝
⊢ ((boolKernel μ ν) b) s✝ = (Measure.sum fun n ↦ (boolKernel (sfiniteSeq μ n) (sfiniteSeq ν n)) b) s✝
Module: Mathlib.Probability.Kernel.Composition.Comp

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
η : Kernel β γ
inst✝¹ : IsMarkovKernel η
κ : Kernel α β
inst✝ : IsMarkovKernel κ
a : α
⊢ IsProbabilityMeasure ((η ∘ₖ κ) a)

Tactic:
by
    rw [comp_apply]
    constructor
    rw [Measure.bind_apply .univ η.aemeasurable]
    simp

Goal state after:
Module: Mathlib.Probability.Kernel.Composition.Comp

Goal state before:
pp: case inl.inl
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
inst✝¹ : IsZeroOrMarkovKernel 0
inst✝ : IsZeroOrMarkovKernel 0
⊢ IsZeroOrMarkovKernel (0 ∘ₖ 0)

pp: case inl.inr
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
η : Kernel β γ
inst✝¹ : IsZeroOrMarkovKernel η
inst✝ : IsZeroOrMarkovKernel 0
h✝ : IsMarkovKernel η
⊢ IsZeroOrMarkovKernel (η ∘ₖ 0)

pp: case inr.inl
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
κ : Kernel α β
inst✝¹ : IsZeroOrMarkovKernel κ
h✝ : IsMarkovKernel κ
inst✝ : IsZeroOrMarkovKernel 0
⊢ IsZeroOrMarkovKernel (0 ∘ₖ κ)

pp: case inr.inr
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
κ : Kernel α β
inst✝¹ : IsZeroOrMarkovKernel κ
η : Kernel β γ
inst✝ : IsZeroOrMarkovKernel η
h✝¹ : IsMarkovKernel κ
h✝ : IsMarkovKernel η
⊢ IsZeroOrMarkovKernel (η ∘ₖ κ)

Tactic:
all_goals simpa using by infer_instance

Goal state after:
Module: Mathlib.Probability.Kernel.Composition.ParallelComp

Goal state before:
pp: case inl.inl
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
mδ : MeasurableSpace δ
x : α × γ
inst✝¹ : IsZeroOrMarkovKernel 0
inst✝ : IsZeroOrMarkovKernel 0
⊢ IsZeroOrMarkovKernel (0 ∥ₖ 0)

pp: case inl.inr
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
mδ : MeasurableSpace δ
η : Kernel γ δ
x : α × γ
inst✝¹ : IsZeroOrMarkovKernel η
inst✝ : IsZeroOrMarkovKernel 0
h✝ : IsMarkovKernel η
⊢ IsZeroOrMarkovKernel (0 ∥ₖ η)

pp: case inr.inl
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
mδ : MeasurableSpace δ
κ : Kernel α β
x : α × γ
inst✝¹ : IsZeroOrMarkovKernel κ
h✝ : IsMarkovKernel κ
inst✝ : IsZeroOrMarkovKernel 0
⊢ IsZeroOrMarkovKernel (κ ∥ₖ 0)

pp: case inr.inr
α : Type u_1
β : Type u_2
γ : Type u_3
δ : Type u_4
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
mδ : MeasurableSpace δ
κ : Kernel α β
η : Kernel γ δ
x : α × γ
inst✝¹ : IsZeroOrMarkovKernel κ
inst✝ : IsZeroOrMarkovKernel η
h✝¹ : IsMarkovKernel κ
h✝ : IsMarkovKernel η
⊢ IsZeroOrMarkovKernel (κ ∥ₖ η)

Tactic:
all_goals simpa using by infer_instance

Goal state after:
Module: Mathlib.Probability.Kernel.Composition.MapComap

Goal state before:
pp: α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
f : α → β
hf : Measurable f
⊢ Kernel.id.map f = deterministic f hf

Tactic:
ext
  rw [Kernel.map_apply _ hf, Kernel.deterministic_apply, Kernel.id_apply, Measure.map_dirac' hf]

Goal state after:
Module: Mathlib.Probability.Kernel.Composition.Prod

Goal state before:
pp: α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
γ : Type u_4
mγ : MeasurableSpace γ
f : α → β
hf : Measurable f
κ : Kernel α γ
inst✝ : IsSFiniteKernel κ
a : α
g : β × γ → ℝ≥0∞
hg : Measurable g
⊢ ∫⁻ (p : β × γ), g p ∂(deterministic f hf ×ₖ κ) a = ∫⁻ (c : γ), g (f a, c) ∂κ a

Tactic:
by
  rw [lintegral_prod _ _ _ hg, lintegral_deterministic' _ hg.lintegral_prod_right']

Goal state after:
Module: Mathlib.Probability.Kernel.Composition.KernelLemmas

Goal state before:
pp: X : Type u_1
Y : Type u_2
Z : Type u_3
mX : MeasurableSpace X
mY : MeasurableSpace Y
mZ : MeasurableSpace Z
κ : Kernel X Y
inst✝¹ : IsSFiniteKernel κ
η : Kernel Y Z
inst✝ : IsSFiniteKernel η
a : X
s : Set (Y × Z)
hs : MeasurableSet s
⊢ ((κ ⊗ₖ prodMkLeft X η) a) s = ((Kernel.id ×ₖ η ∘ₖ κ) a) s

Tactic:
comp_eq_snd_compProd,

Goal state after:
X : Type u_1
Y : Type u_2
Z : Type u_3
mX : MeasurableSpace X
mY : MeasurableSpace Y
mZ : MeasurableSpace Z
κ : Kernel X Y
inst✝¹ : IsSFiniteKernel κ
η : Kernel Y Z
inst✝ : IsSFiniteKernel η
a : X
s : Set (Y × Z)
hs : MeasurableSet s
⊢ ((κ ⊗ₖ prodMkLeft X η) a) s = ((κ ⊗ₖ prodMkLeft X (Kernel.id ×ₖ η)).snd a) s
Module: Mathlib.Probability.Kernel.Composition.MeasureCompProd

Goal state before:
pp: α : Type u_1
β : Type u_2
mα : MeasurableSpace α
mβ : MeasurableSpace β
μ ν : Measure α
κ η : Kernel α β
inst✝¹ : SFinite ν
inst✝ : IsSFiniteKernel η
hμν : μ ≪ ν
hκη : μ ⊗ₘ κ ≪ μ ⊗ₘ η
⊢ μ ⊗ₘ κ ≪ ν ⊗ₘ η

Tactic:
by_cases hμ : SFinite μ
  swap; · rw [compProd_of_not_sfinite _ _ hμ]; simp
  refine AbsolutelyContinuous.mk fun s hs hs_zero ↦ ?_
  suffices (μ ⊗ₘ η) s = 0 from hκη this
  rw [measure_eq_zero_iff_ae_notMem, ae_compProd_iff hs.compl] at hs_zero ⊢
  exact hμν.ae_le hs_zero

Goal state after:
Module: Mathlib.Probability.Kernel.Composition.CompProd

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
κ : Kernel α β
η η' : Kernel (α × β) γ
inst✝¹ : IsSFiniteKernel η
inst✝ : IsSFiniteKernel η'
h : ∀ (a : α), ∀ᵐ (b : β) ∂κ a, η (a, b) = η' (a, b)
hκ : IsSFiniteKernel κ
a : α
s : Set (β × γ)
hs : MeasurableSet s
b : β
⊢ η (a, b) = η' (a, b) → (η (a, b)) (Prod.mk b ⁻¹' s) = (η' (a, b)) (Prod.mk b ⁻¹' s)

Tactic:
hb

Goal state after:
α : Type u_1
β : Type u_2
γ : Type u_3
mα : MeasurableSpace α
mβ : MeasurableSpace β
mγ : MeasurableSpace γ
κ : Kernel α β
η η' : Kernel (α × β) γ
inst✝¹ : IsSFiniteKernel η
inst✝ : IsSFiniteKernel η'
h : ∀ (a : α), ∀ᵐ (b : β) ∂κ a, η (a, b) = η' (a, b)
hκ : IsSFiniteKernel κ
a : α
s : Set (β × γ)
hs : MeasurableSet s
b : β
hb : η (a, b) = η' (a, b)
⊢ (η (a, b)) (Prod.mk b ⁻¹' s) = (η' (a, b)) (Prod.mk b ⁻¹' s)