Theorem: Equiv.Perm.mem_sumCongrHom_range_of_perm_mapsTo_inl
File: Mathlib/GroupTheory/Perm/Finite.lean

tactic: have h1 : ∀ x : Sum m n, (∃ a : m, Sum.inl a = x) → ∃ a : m, Sum.inl a = σ x := by
  rintro x ⟨a, ha⟩
  apply h
  rw [← ha]
  exact ⟨a, rfl⟩
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
⊢ σ ∈ (sumCongrHom m n).range
state_after: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
⊢ σ ∈ (sumCongrHom m n).range

tactic: have h3 : ∀ x : Sum m n, (∃ b : n, Sum.inr b = x) → ∃ b : n, Sum.inr b = σ x := by
  rintro x ⟨b, hb⟩
  apply (perm_mapsTo_inl_iff_mapsTo_inr σ).mp h
  rw [← hb]
  exact ⟨b, rfl⟩
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
⊢ σ ∈ (sumCongrHom m n).range
state_after: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
⊢ σ ∈ (sumCongrHom m n).range

tactic: let σ₁' := subtypePermOfFintype σ h1
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
⊢ σ ∈ (sumCongrHom m n).range
state_after: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
⊢ σ ∈ (sumCongrHom m n).range

tactic: let σ₂' := subtypePermOfFintype σ h3
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
⊢ σ ∈ (sumCongrHom m n).range
state_after: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
⊢ σ ∈ (sumCongrHom m n).range

tactic: let σ₁ := permCongr (Equiv.ofInjective _ Sum.inl_injective).symm σ₁'
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
⊢ σ ∈ (sumCongrHom m n).range
state_after: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
⊢ σ ∈ (sumCongrHom m n).range

tactic: let σ₂ := permCongr (Equiv.ofInjective _ Sum.inr_injective).symm σ₂'
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
⊢ σ ∈ (sumCongrHom m n).range
state_after: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
⊢ σ ∈ (sumCongrHom m n).range

tactic: rw [MonoidHom.mem_range, Prod.exists]
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
⊢ σ ∈ (sumCongrHom m n).range
state_after: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
⊢ ∃ a b, (sumCongrHom m n) (a, b) = σ

tactic: use σ₁, σ₂
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
⊢ ∃ a b, (sumCongrHom m n) (a, b) = σ
state_after: case h
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
⊢ (sumCongrHom m n) (σ₁, σ₂) = σ

tactic: rw [Perm.sumCongrHom_apply]
state_before: case h
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
⊢ (sumCongrHom m n) (σ₁, σ₂) = σ
state_after: case h
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
⊢ (σ₁, σ₂).1.sumCongr (σ₁, σ₂).2 = σ

tactic: ext x
state_before: case h
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
⊢ (σ₁, σ₂).1.sumCongr (σ₁, σ₂).2 = σ
state_after: case h.H
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
x : m ⊕ n
⊢ ((σ₁, σ₂).1.sumCongr (σ₁, σ₂).2) x = σ x

tactic: cases' x with a b
state_before: case h.H
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
x : m ⊕ n
⊢ ((σ₁, σ₂).1.sumCongr (σ₁, σ₂).2) x = σ x
state_after: case h.H.inl
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
a : m
⊢ ((σ₁, σ₂).1.sumCongr (σ₁, σ₂).2) (Sum.inl a) = σ (Sum.inl a)

case h.H.inr
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
b : n
⊢ ((σ₁, σ₂).1.sumCongr (σ₁, σ₂).2) (Sum.inr b) = σ (Sum.inr b)

tactic: rintro x ⟨a, ha⟩
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
⊢ ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
state_after: case intro
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
x : m ⊕ n
a : m
ha : Sum.inl a = x
⊢ ∃ a, Sum.inl a = σ x

tactic: apply h
state_before: case intro
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
x : m ⊕ n
a : m
ha : Sum.inl a = x
⊢ ∃ a, Sum.inl a = σ x
state_after: case intro.a
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
x : m ⊕ n
a : m
ha : Sum.inl a = x
⊢ x ∈ Set.range Sum.inl

tactic: rw [← ha]
state_before: case intro.a
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
x : m ⊕ n
a : m
ha : Sum.inl a = x
⊢ x ∈ Set.range Sum.inl
state_after: case intro.a
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
x : m ⊕ n
a : m
ha : Sum.inl a = x
⊢ Sum.inl a ∈ Set.range Sum.inl

tactic: exact ⟨a, rfl⟩
state_before: case intro.a
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
x : m ⊕ n
a : m
ha : Sum.inl a = x
⊢ Sum.inl a ∈ Set.range Sum.inl
state_after: no goals

tactic: rintro x ⟨b, hb⟩
state_before: α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
⊢ ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
state_after: case intro
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
x : m ⊕ n
b : n
hb : Sum.inr b = x
⊢ ∃ b, Sum.inr b = σ x

tactic: apply (perm_mapsTo_inl_iff_mapsTo_inr σ).mp h
state_before: case intro
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
x : m ⊕ n
b : n
hb : Sum.inr b = x
⊢ ∃ b, Sum.inr b = σ x
state_after: case intro.a
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
x : m ⊕ n
b : n
hb : Sum.inr b = x
⊢ x ∈ Set.range Sum.inr

tactic: rw [← hb]
state_before: case intro.a
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
x : m ⊕ n
b : n
hb : Sum.inr b = x
⊢ x ∈ Set.range Sum.inr
state_after: case intro.a
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
x : m ⊕ n
b : n
hb : Sum.inr b = x
⊢ Sum.inr b ∈ Set.range Sum.inr

tactic: exact ⟨b, rfl⟩
state_before: case intro.a
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
x : m ⊕ n
b : n
hb : Sum.inr b = x
⊢ Sum.inr b ∈ Set.range Sum.inr
state_after: no goals

tactic: rw [Equiv.sumCongr_apply, Sum.map_inl, permCongr_apply, Equiv.symm_symm,
  apply_ofInjective_symm Sum.inl_injective]
state_before: case h.H.inl
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
a : m
⊢ ((σ₁, σ₂).1.sumCongr (σ₁, σ₂).2) (Sum.inl a) = σ (Sum.inl a)
state_after: case h.H.inl
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
a : m
⊢ ↑(σ₁' ((ofInjective Sum.inl ⋯) a)) = σ (Sum.inl a)

tactic: rw [ofInjective_apply, Subtype.coe_mk, Subtype.coe_mk]
state_before: case h.H.inl
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
a : m
⊢ ↑(σ₁' ((ofInjective Sum.inl ⋯) a)) = σ (Sum.inl a)
state_after: case h.H.inl
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
a : m
⊢ ↑(σ₁' ⟨Sum.inl a, ⋯⟩) = σ (Sum.inl a)

tactic: erw [subtypePerm_apply]
state_before: case h.H.inl
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
a : m
⊢ ↑(σ₁' ⟨Sum.inl a, ⋯⟩) = σ (Sum.inl a)
state_after: no goals

tactic: rw [Equiv.sumCongr_apply, Sum.map_inr, permCongr_apply, Equiv.symm_symm,
  apply_ofInjective_symm Sum.inr_injective]
state_before: case h.H.inr
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
b : n
⊢ ((σ₁, σ₂).1.sumCongr (σ₁, σ₂).2) (Sum.inr b) = σ (Sum.inr b)
state_after: case h.H.inr
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
b : n
⊢ ↑(σ₂' ((ofInjective Sum.inr ⋯) b)) = σ (Sum.inr b)

tactic: erw [subtypePerm_apply]
state_before: case h.H.inr
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
b : n
⊢ ↑(σ₂' ((ofInjective Sum.inr ⋯) b)) = σ (Sum.inr b)
state_after: case h.H.inr
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
b : n
⊢ ↑⟨σ ↑((ofInjective Sum.inr ⋯) b), ⋯⟩ = σ (Sum.inr b)

tactic: rw [ofInjective_apply, Subtype.coe_mk, Subtype.coe_mk]
state_before: case h.H.inr
α : Type u
β : Type v
m : Type u_1
n : Type u_2
inst✝¹ : Finite m
inst✝ : Finite n
σ : Perm (m ⊕ n)
h : Set.MapsTo (⇑σ) (Set.range Sum.inl) (Set.range Sum.inl)
h1 : ∀ (x : m ⊕ n), (∃ a, Sum.inl a = x) → ∃ a, Sum.inl a = σ x
h3 : ∀ (x : m ⊕ n), (∃ b, Sum.inr b = x) → ∃ b, Sum.inr b = σ x
σ₁' : Perm { x // ∃ a, Sum.inl a = x } := σ.subtypePermOfFintype h1
σ₂' : Perm { x // ∃ b, Sum.inr b = x } := σ.subtypePermOfFintype h3
σ₁ : Perm m := (ofInjective Sum.inl ⋯).symm.permCongr σ₁'
σ₂ : Perm n := (ofInjective Sum.inr ⋯).symm.permCongr σ₂'
b : n
⊢ ↑⟨σ ↑((ofInjective Sum.inr ⋯) b), ⋯⟩ = σ (Sum.inr b)
state_after: no goals