Theorem: CompositionSeries.Equivalent.snoc
File: Mathlib/Order/JordanHolder.lean

tactic: refine Fin.lastCases ?_ ?_ i
state_before: X : Type u
inst✝¹ : Lattice X
inst✝ : JordanHolderLattice X
s₁ s₂ : CompositionSeries X
x₁ x₂ : X
hsat₁ : IsMaximal (last s₁) x₁
hsat₂ : IsMaximal (last s₂) x₂
hequiv : s₁.Equivalent s₂
hlast : Iso (last s₁, x₁) (last s₂, x₂)
e : Fin s₁.length.succ ≃ Fin s₂.length.succ :=
  Trans.trans (Trans.trans finSuccEquivLast (Functor.mapEquiv Option (Exists.choose hequiv))) finSuccEquivLast.symm
i : Fin (snoc s₁ x₁ hsat₁).length
⊢ Iso ((snoc s₁ x₁ hsat₁).toFun i.castSucc, (snoc s₁ x₁ hsat₁).toFun i.succ)
    ((snoc s₂ x₂ hsat₂).toFun (e i).castSucc, (snoc s₂ x₂ hsat₂).toFun (e i).succ)
state_after: case refine_1
X : Type u
inst✝¹ : Lattice X
inst✝ : JordanHolderLattice X
s₁ s₂ : CompositionSeries X
x₁ x₂ : X
hsat₁ : IsMaximal (last s₁) x₁
hsat₂ : IsMaximal (last s₂) x₂
hequiv : s₁.Equivalent s₂
hlast : Iso (last s₁, x₁) (last s₂, x₂)
e : Fin s₁.length.succ ≃ Fin s₂.length.succ :=
  Trans.trans (Trans.trans finSuccEquivLast (Functor.mapEquiv Option (Exists.choose hequiv))) finSuccEquivLast.symm
i : Fin (snoc s₁ x₁ hsat₁).length
⊢ Iso
    ((snoc s₁ x₁ hsat₁).toFun (Fin.last (s₁.length + (RelSeries.singleton IsMaximal x₁).length)).castSucc,
      (snoc s₁ x₁ hsat₁).toFun (Fin.last (s₁.length + (RelSeries.singleton IsMaximal x₁).length)).succ)
    ((snoc s₂ x₂ hsat₂).toFun (e (Fin.last (s₁.length + (RelSeries.singleton IsMaximal x₁).length))).castSucc,
      (snoc s₂ x₂ hsat₂).toFun (e (Fin.last (s₁.length + (RelSeries.singleton IsMaximal x₁).length))).succ)

case refine_2
X : Type u
inst✝¹ : Lattice X
inst✝ : JordanHolderLattice X
s₁ s₂ : CompositionSeries X
x₁ x₂ : X
hsat₁ : IsMaximal (last s₁) x₁
hsat₂ : IsMaximal (last s₂) x₂
hequiv : s₁.Equivalent s₂
hlast : Iso (last s₁, x₁) (last s₂, x₂)
e : Fin s₁.length.succ ≃ Fin s₂.length.succ :=
  Trans.trans (Trans.trans finSuccEquivLast (Functor.mapEquiv Option (Exists.choose hequiv))) finSuccEquivLast.symm
i : Fin (snoc s₁ x₁ hsat₁).length
⊢ ∀ (i : Fin (s₁.length + (RelSeries.singleton IsMaximal x₁).length)),
    Iso ((snoc s₁ x₁ hsat₁).toFun i.castSucc.castSucc, (snoc s₁ x₁ hsat₁).toFun i.castSucc.succ)
      ((snoc s₂ x₂ hsat₂).toFun (e i.castSucc).castSucc, (snoc s₂ x₂ hsat₂).toFun (e i.castSucc).succ)

tactic: simpa [e, apply_last] using hlast
state_before: case refine_1
X : Type u
inst✝¹ : Lattice X
inst✝ : JordanHolderLattice X
s₁ s₂ : CompositionSeries X
x₁ x₂ : X
hsat₁ : IsMaximal (last s₁) x₁
hsat₂ : IsMaximal (last s₂) x₂
hequiv : s₁.Equivalent s₂
hlast : Iso (last s₁, x₁) (last s₂, x₂)
e : Fin s₁.length.succ ≃ Fin s₂.length.succ :=
  Trans.trans (Trans.trans finSuccEquivLast (Functor.mapEquiv Option (Exists.choose hequiv))) finSuccEquivLast.symm
i : Fin (snoc s₁ x₁ hsat₁).length
⊢ Iso
    ((snoc s₁ x₁ hsat₁).toFun (Fin.last (s₁.length + (RelSeries.singleton IsMaximal x₁).length)).castSucc,
      (snoc s₁ x₁ hsat₁).toFun (Fin.last (s₁.length + (RelSeries.singleton IsMaximal x₁).length)).succ)
    ((snoc s₂ x₂ hsat₂).toFun (e (Fin.last (s₁.length + (RelSeries.singleton IsMaximal x₁).length))).castSucc,
      (snoc s₂ x₂ hsat₂).toFun (e (Fin.last (s₁.length + (RelSeries.singleton IsMaximal x₁).length))).succ)
state_after: no goals

tactic: intro i
state_before: case refine_2
X : Type u
inst✝¹ : Lattice X
inst✝ : JordanHolderLattice X
s₁ s₂ : CompositionSeries X
x₁ x₂ : X
hsat₁ : IsMaximal (last s₁) x₁
hsat₂ : IsMaximal (last s₂) x₂
hequiv : s₁.Equivalent s₂
hlast : Iso (last s₁, x₁) (last s₂, x₂)
e : Fin s₁.length.succ ≃ Fin s₂.length.succ :=
  Trans.trans (Trans.trans finSuccEquivLast (Functor.mapEquiv Option (Exists.choose hequiv))) finSuccEquivLast.symm
i : Fin (snoc s₁ x₁ hsat₁).length
⊢ ∀ (i : Fin (s₁.length + (RelSeries.singleton IsMaximal x₁).length)),
    Iso ((snoc s₁ x₁ hsat₁).toFun i.castSucc.castSucc, (snoc s₁ x₁ hsat₁).toFun i.castSucc.succ)
      ((snoc s₂ x₂ hsat₂).toFun (e i.castSucc).castSucc, (snoc s₂ x₂ hsat₂).toFun (e i.castSucc).succ)
state_after: case refine_2
X : Type u
inst✝¹ : Lattice X
inst✝ : JordanHolderLattice X
s₁ s₂ : CompositionSeries X
x₁ x₂ : X
hsat₁ : IsMaximal (last s₁) x₁
hsat₂ : IsMaximal (last s₂) x₂
hequiv : s₁.Equivalent s₂
hlast : Iso (last s₁, x₁) (last s₂, x₂)
e : Fin s₁.length.succ ≃ Fin s₂.length.succ :=
  Trans.trans (Trans.trans finSuccEquivLast (Functor.mapEquiv Option (Exists.choose hequiv))) finSuccEquivLast.symm
i✝ : Fin (snoc s₁ x₁ hsat₁).length
i : Fin (s₁.length + (RelSeries.singleton IsMaximal x₁).length)
⊢ Iso ((snoc s₁ x₁ hsat₁).toFun i.castSucc.castSucc, (snoc s₁ x₁ hsat₁).toFun i.castSucc.succ)
    ((snoc s₂ x₂ hsat₂).toFun (e i.castSucc).castSucc, (snoc s₂ x₂ hsat₂).toFun (e i.castSucc).succ)

tactic: simpa [e, Fin.succ_castSucc] using hequiv.choose_spec i
state_before: case refine_2
X : Type u
inst✝¹ : Lattice X
inst✝ : JordanHolderLattice X
s₁ s₂ : CompositionSeries X
x₁ x₂ : X
hsat₁ : IsMaximal (last s₁) x₁
hsat₂ : IsMaximal (last s₂) x₂
hequiv : s₁.Equivalent s₂
hlast : Iso (last s₁, x₁) (last s₂, x₂)
e : Fin s₁.length.succ ≃ Fin s₂.length.succ :=
  Trans.trans (Trans.trans finSuccEquivLast (Functor.mapEquiv Option (Exists.choose hequiv))) finSuccEquivLast.symm
i✝ : Fin (snoc s₁ x₁ hsat₁).length
i : Fin (s₁.length + (RelSeries.singleton IsMaximal x₁).length)
⊢ Iso ((snoc s₁ x₁ hsat₁).toFun i.castSucc.castSucc, (snoc s₁ x₁ hsat₁).toFun i.castSucc.succ)
    ((snoc s₂ x₂ hsat₂).toFun (e i.castSucc).castSucc, (snoc s₂ x₂ hsat₂).toFun (e i.castSucc).succ)
state_after: no goals