Documentation

Mathlib.Logic.Equiv.Defs

Equivalence between types #

In this file we define two types:

Then we define

Many more such isomorphisms and operations are defined in Logic.Equiv.Basic.

Tags #

equivalence, congruence, bijective map

structure Equiv (α : Sort u_1) (β : Sort u_2) :
Sort (max (max 1 u_1) u_2)

α ≃ β is the type of functions from α → β with a two-sided inverse.

Instances For

    α ≃ β is the type of functions from α → β with a two-sided inverse.

    Equations
    Instances For
      def EquivLike.toEquiv {α : Sort u} {β : Sort v} {F : Sort u_1} [EquivLike F α β] (f : F) :
      α β

      Turn an element of a type F satisfying EquivLike F α β into an actual Equiv. This is declared as the default coercion from F to α ≃ β.

      Equations
      • f = { toFun := f, invFun := EquivLike.inv f, left_inv := , right_inv := }
      Instances For
        instance instCoeTCEquiv {α : Sort u} {β : Sort v} {F : Sort u_1} [EquivLike F α β] :
        CoeTC F (α β)

        Any type satisfying EquivLike can be cast into Equiv via EquivLike.toEquiv.

        Equations
        • instCoeTCEquiv = { coe := EquivLike.toEquiv }
        @[reducible]
        def Equiv.Perm (α : Sort u_1) :
        Sort (max 1 u_1)

        Perm α is the type of bijections from α to itself.

        Equations
        Instances For
          instance Equiv.instEquivLikeEquiv {α : Sort u} {β : Sort v} :
          EquivLike (α β) α β
          Equations
          • Equiv.instEquivLikeEquiv = { coe := Equiv.toFun, inv := Equiv.invFun, left_inv := , right_inv := , coe_injective' := }
          instance Equiv.instFunLikeEquiv {α : Sort u} {β : Sort v} :
          FunLike (α β) α β

          Helper instance when inference gets stuck on following the normal chain EquivLikeFunLike.

          TODO: this instance doesn't appear to be necessary: remove it (after benchmarking?)

          Equations
          • Equiv.instFunLikeEquiv = { coe := Equiv.toFun, coe_injective' := }
          @[simp]
          theorem EquivLike.coe_coe {α : Sort u} {β : Sort v} {F : Sort u_1} [EquivLike F α β] (e : F) :
          e = e
          @[simp]
          theorem Equiv.coe_fn_mk {α : Sort u} {β : Sort v} (f : αβ) (g : βα) (l : Function.LeftInverse g f) (r : Function.RightInverse g f) :
          { toFun := f, invFun := g, left_inv := l, right_inv := r } = f
          theorem Equiv.coe_fn_injective {α : Sort u} {β : Sort v} :
          Function.Injective fun (e : α β) => e

          The map (r ≃ s) → (r → s) is injective.

          theorem Equiv.coe_inj {α : Sort u} {β : Sort v} {e₁ : α β} {e₂ : α β} :
          e₁ = e₂ e₁ = e₂
          theorem Equiv.ext {α : Sort u} {β : Sort v} {f : α β} {g : α β} (H : ∀ (x : α), f x = g x) :
          f = g
          theorem Equiv.congr_arg {α : Sort u} {β : Sort v} {f : α β} {x : α} {x' : α} :
          x = x'f x = f x'
          theorem Equiv.congr_fun {α : Sort u} {β : Sort v} {f : α β} {g : α β} (h : f = g) (x : α) :
          f x = g x
          theorem Equiv.ext_iff {α : Sort u} {β : Sort v} {f : α β} {g : α β} :
          f = g ∀ (x : α), f x = g x
          theorem Equiv.Perm.ext {α : Sort u} {σ : Equiv.Perm α} {τ : Equiv.Perm α} (H : ∀ (x : α), σ x = τ x) :
          σ = τ
          theorem Equiv.Perm.congr_arg {α : Sort u} {f : Equiv.Perm α} {x : α} {x' : α} :
          x = x'f x = f x'
          theorem Equiv.Perm.congr_fun {α : Sort u} {f : Equiv.Perm α} {g : Equiv.Perm α} (h : f = g) (x : α) :
          f x = g x
          theorem Equiv.Perm.ext_iff {α : Sort u} {σ : Equiv.Perm α} {τ : Equiv.Perm α} :
          σ = τ ∀ (x : α), σ x = τ x
          def Equiv.refl (α : Sort u_1) :
          α α

          Any type is equivalent to itself.

          Equations
          • Equiv.refl α = { toFun := id, invFun := id, left_inv := , right_inv := }
          Instances For
            instance Equiv.inhabited' {α : Sort u} :
            Inhabited (α α)
            Equations
            def Equiv.symm {α : Sort u} {β : Sort v} (e : α β) :
            β α

            Inverse of an equivalence e : α ≃ β.

            Equations
            • e.symm = { toFun := e.invFun, invFun := e.toFun, left_inv := , right_inv := }
            Instances For
              def Equiv.Simps.symm_apply {α : Sort u} {β : Sort v} (e : α β) :
              βα

              See Note [custom simps projection]

              Equations
              Instances For
                theorem Equiv.left_inv' {α : Sort u} {β : Sort v} (e : α β) :
                Function.LeftInverse e.symm e
                theorem Equiv.right_inv' {α : Sort u} {β : Sort v} (e : α β) :
                Function.RightInverse e.symm e
                def Equiv.trans {α : Sort u} {β : Sort v} {γ : Sort w} (e₁ : α β) (e₂ : β γ) :
                α γ

                Composition of equivalences e₁ : α ≃ β and e₂ : β ≃ γ.

                Equations
                • e₁.trans e₂ = { toFun := e₂ e₁, invFun := e₁.symm e₂.symm, left_inv := , right_inv := }
                Instances For
                  @[simp]
                  theorem Equiv.instTransSortSortSortEquivEquivEquiv_trans :
                  ∀ {a : Sort u_2} {b : Sort u_1} {c : Sort u_3} (e₁ : a b) (e₂ : b c), Trans.trans e₁ e₂ = e₁.trans e₂
                  Equations
                  @[simp]
                  theorem Equiv.toFun_as_coe {α : Sort u} {β : Sort v} (e : α β) :
                  e.toFun = e
                  @[simp]
                  theorem Equiv.invFun_as_coe {α : Sort u} {β : Sort v} (e : α β) :
                  e.invFun = e.symm
                  theorem Equiv.injective {α : Sort u} {β : Sort v} (e : α β) :
                  theorem Equiv.surjective {α : Sort u} {β : Sort v} (e : α β) :
                  theorem Equiv.bijective {α : Sort u} {β : Sort v} (e : α β) :
                  theorem Equiv.subsingleton {α : Sort u} {β : Sort v} (e : α β) [Subsingleton β] :
                  theorem Equiv.subsingleton.symm {α : Sort u} {β : Sort v} (e : α β) [Subsingleton α] :
                  theorem Equiv.subsingleton_congr {α : Sort u} {β : Sort v} (e : α β) :
                  instance Equiv.equiv_subsingleton_cod {α : Sort u} {β : Sort v} [Subsingleton β] :
                  Equations
                  • =
                  instance Equiv.equiv_subsingleton_dom {α : Sort u} {β : Sort v} [Subsingleton α] :
                  Equations
                  • =
                  instance Equiv.permUnique {α : Sort u} [Subsingleton α] :
                  Equations
                  def Equiv.decidableEq {α : Sort u} {β : Sort v} (e : α β) [DecidableEq β] :

                  Transfer DecidableEq across an equivalence.

                  Equations
                  Instances For
                    theorem Equiv.nonempty_congr {α : Sort u} {β : Sort v} (e : α β) :
                    theorem Equiv.nonempty {α : Sort u} {β : Sort v} (e : α β) [Nonempty β] :
                    def Equiv.inhabited {α : Sort u} {β : Sort v} [Inhabited β] (e : α β) :

                    If α ≃ β and β is inhabited, then so is α.

                    Equations
                    Instances For
                      def Equiv.unique {α : Sort u} {β : Sort v} [Unique β] (e : α β) :

                      If α ≃ β and β is a singleton type, then so is α.

                      Equations
                      Instances For
                        def Equiv.cast {α : Sort u_1} {β : Sort u_1} (h : α = β) :
                        α β

                        Equivalence between equal types.

                        Equations
                        Instances For
                          @[simp]
                          theorem Equiv.coe_fn_symm_mk {α : Sort u} {β : Sort v} (f : αβ) (g : βα) (l : Function.LeftInverse g f) (r : Function.RightInverse g f) :
                          { toFun := f, invFun := g, left_inv := l, right_inv := r }.symm = g
                          @[simp]
                          theorem Equiv.coe_refl {α : Sort u} :
                          (Equiv.refl α) = id
                          theorem Equiv.Perm.coe_subsingleton {α : Type u_1} [Subsingleton α] (e : Equiv.Perm α) :
                          e = id

                          This cannot be a simp lemmas as it incorrectly matches against e : α ≃ synonym α, when synonym α is semireducible. This makes a mess of Multiplicative.ofAdd etc.

                          @[simp]
                          theorem Equiv.refl_apply {α : Sort u} (x : α) :
                          (Equiv.refl α) x = x
                          @[simp]
                          theorem Equiv.coe_trans {α : Sort u} {β : Sort v} {γ : Sort w} (f : α β) (g : β γ) :
                          (f.trans g) = g f
                          @[simp]
                          theorem Equiv.trans_apply {α : Sort u} {β : Sort v} {γ : Sort w} (f : α β) (g : β γ) (a : α) :
                          (f.trans g) a = g (f a)
                          @[simp]
                          theorem Equiv.apply_symm_apply {α : Sort u} {β : Sort v} (e : α β) (x : β) :
                          e (e.symm x) = x
                          @[simp]
                          theorem Equiv.symm_apply_apply {α : Sort u} {β : Sort v} (e : α β) (x : α) :
                          e.symm (e x) = x
                          @[simp]
                          theorem Equiv.symm_comp_self {α : Sort u} {β : Sort v} (e : α β) :
                          e.symm e = id
                          @[simp]
                          theorem Equiv.self_comp_symm {α : Sort u} {β : Sort v} (e : α β) :
                          e e.symm = id
                          @[simp]
                          theorem EquivLike.apply_coe_symm_apply {α : Sort u} {β : Sort v} {F : Sort u_1} [EquivLike F α β] (e : F) (x : β) :
                          e ((e).symm x) = x
                          @[simp]
                          theorem EquivLike.coe_symm_apply_apply {α : Sort u} {β : Sort v} {F : Sort u_1} [EquivLike F α β] (e : F) (x : α) :
                          (e).symm (e x) = x
                          @[simp]
                          theorem EquivLike.coe_symm_comp_self {α : Sort u} {β : Sort v} {F : Sort u_1} [EquivLike F α β] (e : F) :
                          (e).symm e = id
                          @[simp]
                          theorem EquivLike.self_comp_coe_symm {α : Sort u} {β : Sort v} {F : Sort u_1} [EquivLike F α β] (e : F) :
                          e (e).symm = id
                          @[simp]
                          theorem Equiv.symm_trans_apply {α : Sort u} {β : Sort v} {γ : Sort w} (f : α β) (g : β γ) (a : γ) :
                          (f.trans g).symm a = f.symm (g.symm a)
                          @[simp]
                          theorem Equiv.symm_symm_apply {α : Sort u} {β : Sort v} (f : α β) (b : α) :
                          f.symm.symm b = f b
                          theorem Equiv.apply_eq_iff_eq {α : Sort u} {β : Sort v} (f : α β) {x : α} {y : α} :
                          f x = f y x = y
                          theorem Equiv.apply_eq_iff_eq_symm_apply {α : Sort u} {β : Sort v} {x : α} {y : β} (f : α β) :
                          f x = y x = f.symm y
                          @[simp]
                          theorem Equiv.cast_apply {α : Sort u_1} {β : Sort u_1} (h : α = β) (x : α) :
                          (Equiv.cast h) x = cast h x
                          @[simp]
                          theorem Equiv.cast_symm {α : Sort u_1} {β : Sort u_1} (h : α = β) :
                          (Equiv.cast h).symm = Equiv.cast
                          @[simp]
                          theorem Equiv.cast_refl {α : Sort u_1} (h : optParam (α = α) ) :
                          @[simp]
                          theorem Equiv.cast_trans {α : Sort u_1} {β : Sort u_1} {γ : Sort u_1} (h : α = β) (h2 : β = γ) :
                          (Equiv.cast h).trans (Equiv.cast h2) = Equiv.cast
                          theorem Equiv.cast_eq_iff_heq {α : Sort u_1} {β : Sort u_1} (h : α = β) {a : α} {b : β} :
                          (Equiv.cast h) a = b HEq a b
                          theorem Equiv.symm_apply_eq {α : Sort u_1} {β : Sort u_2} (e : α β) {x : β} {y : α} :
                          e.symm x = y x = e y
                          theorem Equiv.eq_symm_apply {α : Sort u_1} {β : Sort u_2} (e : α β) {x : β} {y : α} :
                          y = e.symm x e y = x
                          @[simp]
                          theorem Equiv.symm_symm {α : Sort u} {β : Sort v} (e : α β) :
                          e.symm.symm = e
                          theorem Equiv.symm_bijective {α : Sort u} {β : Sort v} :
                          @[simp]
                          theorem Equiv.trans_refl {α : Sort u} {β : Sort v} (e : α β) :
                          e.trans (Equiv.refl β) = e
                          @[simp]
                          theorem Equiv.refl_symm {α : Sort u} :
                          (Equiv.refl α).symm = Equiv.refl α
                          @[simp]
                          theorem Equiv.refl_trans {α : Sort u} {β : Sort v} (e : α β) :
                          (Equiv.refl α).trans e = e
                          @[simp]
                          theorem Equiv.symm_trans_self {α : Sort u} {β : Sort v} (e : α β) :
                          e.symm.trans e = Equiv.refl β
                          @[simp]
                          theorem Equiv.self_trans_symm {α : Sort u} {β : Sort v} (e : α β) :
                          e.trans e.symm = Equiv.refl α
                          theorem Equiv.trans_assoc {α : Sort u} {β : Sort v} {γ : Sort w} {δ : Sort u_1} (ab : α β) (bc : β γ) (cd : γ δ) :
                          (ab.trans bc).trans cd = ab.trans (bc.trans cd)
                          theorem Equiv.leftInverse_symm {α : Sort u} {β : Sort v} (f : α β) :
                          Function.LeftInverse f.symm f
                          theorem Equiv.rightInverse_symm {α : Sort u} {β : Sort v} (f : α β) :
                          Function.RightInverse f.symm f
                          theorem Equiv.injective_comp {α : Sort u} {β : Sort v} {γ : Sort w} (e : α β) (f : βγ) :
                          theorem Equiv.comp_injective {α : Sort u} {β : Sort v} {γ : Sort w} (f : αβ) (e : β γ) :
                          theorem Equiv.surjective_comp {α : Sort u} {β : Sort v} {γ : Sort w} (e : α β) (f : βγ) :
                          theorem Equiv.comp_surjective {α : Sort u} {β : Sort v} {γ : Sort w} (f : αβ) (e : β γ) :
                          theorem Equiv.bijective_comp {α : Sort u} {β : Sort v} {γ : Sort w} (e : α β) (f : βγ) :
                          theorem Equiv.comp_bijective {α : Sort u} {β : Sort v} {γ : Sort w} (f : αβ) (e : β γ) :
                          def Equiv.equivCongr {α : Sort u} {β : Sort v} {γ : Sort w} {δ : Sort u_1} (ab : α β) (cd : γ δ) :
                          α γ (β δ)

                          If α is equivalent to β and γ is equivalent to δ, then the type of equivalences α ≃ γ is equivalent to the type of equivalences β ≃ δ.

                          Equations
                          • Equiv.equivCongr ab cd = { toFun := fun (ac : α γ) => (ab.symm.trans ac).trans cd, invFun := fun (bd : β δ) => ab.trans (bd.trans cd.symm), left_inv := , right_inv := }
                          Instances For
                            @[simp]
                            theorem Equiv.equivCongr_refl {α : Sort u_1} {β : Sort u_2} :
                            @[simp]
                            theorem Equiv.equivCongr_symm {α : Sort u} {β : Sort v} {γ : Sort w} {δ : Sort u_1} (ab : α β) (cd : γ δ) :
                            (Equiv.equivCongr ab cd).symm = Equiv.equivCongr ab.symm cd.symm
                            @[simp]
                            theorem Equiv.equivCongr_trans {α : Sort u} {β : Sort v} {γ : Sort w} {δ : Sort u_1} {ε : Sort u_2} {ζ : Sort u_3} (ab : α β) (de : δ ε) (bc : β γ) (ef : ε ζ) :
                            (Equiv.equivCongr ab de).trans (Equiv.equivCongr bc ef) = Equiv.equivCongr (ab.trans bc) (de.trans ef)
                            @[simp]
                            theorem Equiv.equivCongr_refl_left {α : Sort u_1} {β : Sort u_2} {γ : Sort u_3} (bg : β γ) (e : α β) :
                            (Equiv.equivCongr (Equiv.refl α) bg) e = e.trans bg
                            @[simp]
                            theorem Equiv.equivCongr_refl_right {α : Sort u_1} {β : Sort u_2} (ab : α β) (e : α β) :
                            (Equiv.equivCongr ab (Equiv.refl β)) e = ab.symm.trans e
                            @[simp]
                            theorem Equiv.equivCongr_apply_apply {α : Sort u} {β : Sort v} {γ : Sort w} {δ : Sort u_1} (ab : α β) (cd : γ δ) (e : α γ) (x : β) :
                            ((Equiv.equivCongr ab cd) e) x = cd (e (ab.symm x))
                            def Equiv.permCongr {α' : Type u_1} {β' : Type u_2} (e : α' β') :

                            If α is equivalent to β, then Perm α is equivalent to Perm β.

                            Equations
                            Instances For
                              theorem Equiv.permCongr_def {α' : Type u_1} {β' : Type u_2} (e : α' β') (p : Equiv.Perm α') :
                              (Equiv.permCongr e) p = (e.symm.trans p).trans e
                              @[simp]
                              theorem Equiv.permCongr_refl {α' : Type u_1} {β' : Type u_2} (e : α' β') :
                              @[simp]
                              theorem Equiv.permCongr_symm {α' : Type u_1} {β' : Type u_2} (e : α' β') :
                              @[simp]
                              theorem Equiv.permCongr_apply {α' : Type u_1} {β' : Type u_2} (e : α' β') (p : Equiv.Perm α') (x : β') :
                              ((Equiv.permCongr e) p) x = e (p (e.symm x))
                              theorem Equiv.permCongr_symm_apply {α' : Type u_1} {β' : Type u_2} (e : α' β') (p : Equiv.Perm β') (x : α') :
                              ((Equiv.permCongr e).symm p) x = e.symm (p (e x))
                              theorem Equiv.permCongr_trans {α' : Type u_1} {β' : Type u_2} (e : α' β') (p : Equiv.Perm α') (p' : Equiv.Perm α') :
                              ((Equiv.permCongr e) p).trans ((Equiv.permCongr e) p') = (Equiv.permCongr e) (p.trans p')
                              def Equiv.equivOfIsEmpty (α : Sort u_1) (β : Sort u_2) [IsEmpty α] [IsEmpty β] :
                              α β

                              Two empty types are equivalent.

                              Equations
                              Instances For
                                def Equiv.equivEmpty (α : Sort u) [IsEmpty α] :

                                If α is an empty type, then it is equivalent to the Empty type.

                                Equations
                                Instances For

                                  If α is an empty type, then it is equivalent to the PEmpty type in any universe.

                                  Equations
                                  Instances For

                                    α is equivalent to an empty type iff α is empty.

                                    Equations
                                    Instances For

                                      The Sort of proofs of a false proposition is equivalent to PEmpty.

                                      Equations
                                      Instances For
                                        def Equiv.equivOfUnique (α : Sort u) (β : Sort v) [Unique α] [Unique β] :
                                        α β

                                        If both α and β have a unique element, then α ≃ β.

                                        Equations
                                        • Equiv.equivOfUnique α β = { toFun := default, invFun := default, left_inv := , right_inv := }
                                        Instances For
                                          def Equiv.equivPUnit (α : Sort u) [Unique α] :

                                          If α has a unique element, then it is equivalent to any PUnit.

                                          Equations
                                          Instances For
                                            def Equiv.propEquivPUnit {p : Prop} (h : p) :

                                            The Sort of proofs of a true proposition is equivalent to PUnit.

                                            Equations
                                            Instances For
                                              @[simp]
                                              theorem Equiv.ulift_apply {α : Type v} :
                                              Equiv.ulift = ULift.down
                                              def Equiv.ulift {α : Type v} :

                                              ULift α is equivalent to α.

                                              Equations
                                              • Equiv.ulift = { toFun := ULift.down, invFun := ULift.up, left_inv := , right_inv := }
                                              Instances For
                                                @[simp]
                                                theorem Equiv.plift_apply {α : Sort u} :
                                                Equiv.plift = PLift.down
                                                def Equiv.plift {α : Sort u} :
                                                PLift α α

                                                PLift α is equivalent to α.

                                                Equations
                                                • Equiv.plift = { toFun := PLift.down, invFun := PLift.up, left_inv := , right_inv := }
                                                Instances For
                                                  def Equiv.ofIff {P : Prop} {Q : Prop} (h : P Q) :
                                                  P Q

                                                  equivalence of propositions is the same as iff

                                                  Equations
                                                  • Equiv.ofIff h = { toFun := , invFun := , left_inv := , right_inv := }
                                                  Instances For
                                                    @[simp]
                                                    theorem Equiv.arrowCongr_apply {α₁ : Sort u_1} {β₁ : Sort u_2} {α₂ : Sort u_3} {β₂ : Sort u_4} (e₁ : α₁ α₂) (e₂ : β₁ β₂) (f : α₁β₁) :
                                                    ∀ (a : α₂), (Equiv.arrowCongr e₁ e₂) f a = (e₂ f e₁.symm) a
                                                    def Equiv.arrowCongr {α₁ : Sort u_1} {β₁ : Sort u_2} {α₂ : Sort u_3} {β₂ : Sort u_4} (e₁ : α₁ α₂) (e₂ : β₁ β₂) :
                                                    (α₁β₁) (α₂β₂)

                                                    If α₁ is equivalent to α₂ and β₁ is equivalent to β₂, then the type of maps α₁ → β₁ is equivalent to the type of maps α₂ → β₂.

                                                    Equations
                                                    • Equiv.arrowCongr e₁ e₂ = { toFun := fun (f : α₁β₁) => e₂ f e₁.symm, invFun := fun (f : α₂β₂) => e₂.symm f e₁, left_inv := , right_inv := }
                                                    Instances For
                                                      theorem Equiv.arrowCongr_comp {α₁ : Sort u_1} {β₁ : Sort u_2} {γ₁ : Sort u_3} {α₂ : Sort u_4} {β₂ : Sort u_5} {γ₂ : Sort u_6} (ea : α₁ α₂) (eb : β₁ β₂) (ec : γ₁ γ₂) (f : α₁β₁) (g : β₁γ₁) :
                                                      (Equiv.arrowCongr ea ec) (g f) = (Equiv.arrowCongr eb ec) g (Equiv.arrowCongr ea eb) f
                                                      @[simp]
                                                      theorem Equiv.arrowCongr_refl {α : Sort u_1} {β : Sort u_2} :
                                                      @[simp]
                                                      theorem Equiv.arrowCongr_trans {α₁ : Sort u_1} {α₂ : Sort u_2} {β₁ : Sort u_3} {β₂ : Sort u_4} {α₃ : Sort u_5} {β₃ : Sort u_6} (e₁ : α₁ α₂) (e₁' : β₁ β₂) (e₂ : α₂ α₃) (e₂' : β₂ β₃) :
                                                      Equiv.arrowCongr (e₁.trans e₂) (e₁'.trans e₂') = (Equiv.arrowCongr e₁ e₁').trans (Equiv.arrowCongr e₂ e₂')
                                                      @[simp]
                                                      theorem Equiv.arrowCongr_symm {α₁ : Sort u_1} {α₂ : Sort u_2} {β₁ : Sort u_3} {β₂ : Sort u_4} (e₁ : α₁ α₂) (e₂ : β₁ β₂) :
                                                      (Equiv.arrowCongr e₁ e₂).symm = Equiv.arrowCongr e₁.symm e₂.symm
                                                      @[simp]
                                                      theorem Equiv.arrowCongr'_apply {α₁ : Type u_1} {β₁ : Type u_2} {α₂ : Type u_3} {β₂ : Type u_4} (hα : α₁ α₂) (hβ : β₁ β₂) (f : α₁β₁) :
                                                      ∀ (a : α₂), (Equiv.arrowCongr' ) f a = (f (.symm a))
                                                      def Equiv.arrowCongr' {α₁ : Type u_1} {β₁ : Type u_2} {α₂ : Type u_3} {β₂ : Type u_4} (hα : α₁ α₂) (hβ : β₁ β₂) :
                                                      (α₁β₁) (α₂β₂)

                                                      A version of Equiv.arrowCongr in Type, rather than Sort.

                                                      The equiv_rw tactic is not able to use the default Sort level Equiv.arrowCongr, because Lean's universe rules will not unify ?l_1 with imax (1 ?m_1).

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                                                        @[simp]
                                                        theorem Equiv.arrowCongr'_refl {α : Type u_1} {β : Type u_2} :
                                                        @[simp]
                                                        theorem Equiv.arrowCongr'_trans {α₁ : Type u_1} {α₂ : Type u_2} {β₁ : Type u_3} {β₂ : Type u_4} {α₃ : Type u_5} {β₃ : Type u_6} (e₁ : α₁ α₂) (e₁' : β₁ β₂) (e₂ : α₂ α₃) (e₂' : β₂ β₃) :
                                                        Equiv.arrowCongr' (e₁.trans e₂) (e₁'.trans e₂') = (Equiv.arrowCongr' e₁ e₁').trans (Equiv.arrowCongr' e₂ e₂')
                                                        @[simp]
                                                        theorem Equiv.arrowCongr'_symm {α₁ : Type u_1} {α₂ : Type u_2} {β₁ : Type u_3} {β₂ : Type u_4} (e₁ : α₁ α₂) (e₂ : β₁ β₂) :
                                                        (Equiv.arrowCongr' e₁ e₂).symm = Equiv.arrowCongr' e₁.symm e₂.symm
                                                        @[simp]
                                                        theorem Equiv.conj_apply {α : Sort u} {β : Sort v} (e : α β) (f : αα) :
                                                        ∀ (a : β), (Equiv.conj e) f a = e (f (e.symm a))
                                                        def Equiv.conj {α : Sort u} {β : Sort v} (e : α β) :
                                                        (αα) (ββ)

                                                        Conjugate a map f : α → α by an equivalence α ≃ β.

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                                                          @[simp]
                                                          theorem Equiv.conj_refl {α : Sort u} :
                                                          @[simp]
                                                          theorem Equiv.conj_symm {α : Sort u} {β : Sort v} (e : α β) :
                                                          (Equiv.conj e).symm = Equiv.conj e.symm
                                                          @[simp]
                                                          theorem Equiv.conj_trans {α : Sort u} {β : Sort v} {γ : Sort w} (e₁ : α β) (e₂ : β γ) :
                                                          Equiv.conj (e₁.trans e₂) = (Equiv.conj e₁).trans (Equiv.conj e₂)
                                                          theorem Equiv.conj_comp {α : Sort u} {β : Sort v} (e : α β) (f₁ : αα) (f₂ : αα) :
                                                          (Equiv.conj e) (f₁ f₂) = (Equiv.conj e) f₁ (Equiv.conj e) f₂
                                                          theorem Equiv.eq_comp_symm {α : Sort u_1} {β : Sort u_2} {γ : Sort u_3} (e : α β) (f : βγ) (g : αγ) :
                                                          f = g e.symm f e = g
                                                          theorem Equiv.comp_symm_eq {α : Sort u_1} {β : Sort u_2} {γ : Sort u_3} (e : α β) (f : βγ) (g : αγ) :
                                                          g e.symm = f g = f e
                                                          theorem Equiv.eq_symm_comp {α : Sort u_1} {β : Sort u_2} {γ : Sort u_3} (e : α β) (f : γα) (g : γβ) :
                                                          f = e.symm g e f = g
                                                          theorem Equiv.symm_comp_eq {α : Sort u_1} {β : Sort u_2} {γ : Sort u_3} (e : α β) (f : γα) (g : γβ) :
                                                          e.symm g = f g = e f

                                                          PUnit sorts in any two universes are equivalent.

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                                                          • One or more equations did not get rendered due to their size.
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                                                            noncomputable def Equiv.propEquivBool :

                                                            Prop is noncomputably equivalent to Bool.

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                                                              The sort of maps to PUnit.{v} is equivalent to PUnit.{w}.

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                                                                @[simp]
                                                                theorem Equiv.piUnique_symm_apply {α : Sort u} [Unique α] (β : αSort u_1) :
                                                                (Equiv.piUnique β).symm = uniqueElim
                                                                @[simp]
                                                                theorem Equiv.piUnique_apply {α : Sort u} [Unique α] (β : αSort u_1) :
                                                                (Equiv.piUnique β) = fun (f : (i : α) → β i) => f default
                                                                def Equiv.piUnique {α : Sort u} [Unique α] (β : αSort u_1) :
                                                                ((i : α) → β i) β default

                                                                The equivalence (∀ i, β i) ≃ β ⋆ when the domain of β only contains

                                                                Equations
                                                                • Equiv.piUnique β = { toFun := fun (f : (i : α) → β i) => f default, invFun := uniqueElim, left_inv := , right_inv := }
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                                                                  @[simp]
                                                                  theorem Equiv.funUnique_apply (α : Sort u) (β : Sort u_1) [Unique α] :
                                                                  (Equiv.funUnique α β) = fun (f : αβ) => f default
                                                                  @[simp]
                                                                  theorem Equiv.funUnique_symm_apply (α : Sort u) (β : Sort u_1) [Unique α] :
                                                                  (Equiv.funUnique α β).symm = uniqueElim
                                                                  def Equiv.funUnique (α : Sort u) (β : Sort u_1) [Unique α] :
                                                                  (αβ) β

                                                                  If α has a unique term, then the type of function α → β is equivalent to β.

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                                                                    def Equiv.punitArrowEquiv (α : Sort u_1) :
                                                                    (PUnit.{u}α) α

                                                                    The sort of maps from PUnit is equivalent to the codomain.

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                                                                      def Equiv.trueArrowEquiv (α : Sort u_1) :
                                                                      (Trueα) α

                                                                      The sort of maps from True is equivalent to the codomain.

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                                                                        def Equiv.arrowPUnitOfIsEmpty (α : Sort u_1) (β : Sort u_2) [IsEmpty α] :
                                                                        (αβ) PUnit.{u}

                                                                        The sort of maps from a type that IsEmpty is equivalent to PUnit.

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                                                                          The sort of maps from Empty is equivalent to PUnit.

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                                                                            The sort of maps from PEmpty is equivalent to PUnit.

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                                                                              The sort of maps from False is equivalent to PUnit.

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                                                                                @[simp]
                                                                                theorem Equiv.psigmaEquivSigma_symm_apply {α : Type u_2} (β : αType u_1) (a : (i : α) × β i) :
                                                                                (Equiv.psigmaEquivSigma β).symm a = { fst := a.fst, snd := a.snd }
                                                                                @[simp]
                                                                                theorem Equiv.psigmaEquivSigma_apply {α : Type u_2} (β : αType u_1) (a : (i : α) ×' β i) :
                                                                                (Equiv.psigmaEquivSigma β) a = { fst := a.fst, snd := a.snd }
                                                                                def Equiv.psigmaEquivSigma {α : Type u_2} (β : αType u_1) :
                                                                                (i : α) ×' β i (i : α) × β i

                                                                                A PSigma-type is equivalent to the corresponding Sigma-type.

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                                                                                • One or more equations did not get rendered due to their size.
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                                                                                  @[simp]
                                                                                  theorem Equiv.psigmaEquivSigmaPLift_symm_apply {α : Sort u_2} (β : αSort u_1) (a : (i : PLift α) × PLift (β i.down)) :
                                                                                  (Equiv.psigmaEquivSigmaPLift β).symm a = { fst := a.fst.down, snd := a.snd.down }
                                                                                  @[simp]
                                                                                  theorem Equiv.psigmaEquivSigmaPLift_apply {α : Sort u_2} (β : αSort u_1) (a : (i : α) ×' β i) :
                                                                                  (Equiv.psigmaEquivSigmaPLift β) a = { fst := { down := a.fst }, snd := { down := a.snd } }
                                                                                  def Equiv.psigmaEquivSigmaPLift {α : Sort u_2} (β : αSort u_1) :
                                                                                  (i : α) ×' β i (i : PLift α) × PLift (β i.down)

                                                                                  A PSigma-type is equivalent to the corresponding Sigma-type.

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                                                                                  • One or more equations did not get rendered due to their size.
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                                                                                    @[simp]
                                                                                    theorem Equiv.psigmaCongrRight_apply {α : Sort u} {β₁ : αSort u_1} {β₂ : αSort u_2} (F : (a : α) → β₁ a β₂ a) (a : (a : α) ×' β₁ a) :
                                                                                    (Equiv.psigmaCongrRight F) a = { fst := a.fst, snd := (F a.fst) a.snd }
                                                                                    def Equiv.psigmaCongrRight {α : Sort u} {β₁ : αSort u_1} {β₂ : αSort u_2} (F : (a : α) → β₁ a β₂ a) :
                                                                                    (a : α) ×' β₁ a (a : α) ×' β₂ a

                                                                                    A family of equivalences Π a, β₁ a ≃ β₂ a generates an equivalence between Σ' a, β₁ a and Σ' a, β₂ a.

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                                                                                    • One or more equations did not get rendered due to their size.
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                                                                                      theorem Equiv.psigmaCongrRight_trans {α : Sort u_4} {β₁ : αSort u_1} {β₂ : αSort u_2} {β₃ : αSort u_3} (F : (a : α) → β₁ a β₂ a) (G : (a : α) → β₂ a β₃ a) :
                                                                                      (Equiv.psigmaCongrRight F).trans (Equiv.psigmaCongrRight G) = Equiv.psigmaCongrRight fun (a : α) => (F a).trans (G a)
                                                                                      theorem Equiv.psigmaCongrRight_symm {α : Sort u_3} {β₁ : αSort u_1} {β₂ : αSort u_2} (F : (a : α) → β₁ a β₂ a) :
                                                                                      (Equiv.psigmaCongrRight F).symm = Equiv.psigmaCongrRight fun (a : α) => (F a).symm
                                                                                      theorem Equiv.psigmaCongrRight_refl {α : Sort u_2} {β : αSort u_1} :
                                                                                      (Equiv.psigmaCongrRight fun (a : α) => Equiv.refl (β a)) = Equiv.refl ((a : α) ×' β a)
                                                                                      @[simp]
                                                                                      theorem Equiv.sigmaCongrRight_apply {α : Type u_3} {β₁ : αType u_1} {β₂ : αType u_2} (F : (a : α) → β₁ a β₂ a) (a : (a : α) × β₁ a) :
                                                                                      (Equiv.sigmaCongrRight F) a = { fst := a.fst, snd := (F a.fst) a.snd }
                                                                                      def Equiv.sigmaCongrRight {α : Type u_3} {β₁ : αType u_1} {β₂ : αType u_2} (F : (a : α) → β₁ a β₂ a) :
                                                                                      (a : α) × β₁ a (a : α) × β₂ a

                                                                                      A family of equivalences Π a, β₁ a ≃ β₂ a generates an equivalence between Σ a, β₁ a and Σ a, β₂ a.

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                                                                                      • One or more equations did not get rendered due to their size.
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                                                                                        theorem Equiv.sigmaCongrRight_trans {α : Type u_4} {β₁ : αType u_1} {β₂ : αType u_2} {β₃ : αType u_3} (F : (a : α) → β₁ a β₂ a) (G : (a : α) → β₂ a β₃ a) :
                                                                                        (Equiv.sigmaCongrRight F).trans (Equiv.sigmaCongrRight G) = Equiv.sigmaCongrRight fun (a : α) => (F a).trans (G a)
                                                                                        theorem Equiv.sigmaCongrRight_symm {α : Type u_3} {β₁ : αType u_1} {β₂ : αType u_2} (F : (a : α) → β₁ a β₂ a) :
                                                                                        (Equiv.sigmaCongrRight F).symm = Equiv.sigmaCongrRight fun (a : α) => (F a).symm
                                                                                        theorem Equiv.sigmaCongrRight_refl {α : Type u_2} {β : αType u_1} :
                                                                                        (Equiv.sigmaCongrRight fun (a : α) => Equiv.refl (β a)) = Equiv.refl ((a : α) × β a)
                                                                                        def Equiv.psigmaEquivSubtype {α : Type v} (P : αProp) :
                                                                                        (i : α) ×' P i Subtype P

                                                                                        A PSigma with Prop fibers is equivalent to the subtype.

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                                                                                          def Equiv.sigmaPLiftEquivSubtype {α : Type v} (P : αProp) :
                                                                                          (i : α) × PLift (P i) Subtype P

                                                                                          A Sigma with PLift fibers is equivalent to the subtype.

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                                                                                          • One or more equations did not get rendered due to their size.
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                                                                                            def Equiv.sigmaULiftPLiftEquivSubtype {α : Type v} (P : αProp) :
                                                                                            (i : α) × ULift.{u_1, 0} (PLift (P i)) Subtype P

                                                                                            A Sigma with fun i ↦ ULift (PLift (P i)) fibers is equivalent to { x // P x }. Variant of sigmaPLiftEquivSubtype.

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                                                                                              @[reducible]
                                                                                              def Equiv.Perm.sigmaCongrRight {α : Type u_1} {β : αType u_2} (F : (a : α) → Equiv.Perm (β a)) :
                                                                                              Equiv.Perm ((a : α) × β a)

                                                                                              A family of permutations Π a, Perm (β a) generates a permutation Perm (Σ a, β₁ a).

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                                                                                                @[simp]
                                                                                                theorem Equiv.Perm.sigmaCongrRight_trans {α : Type u_1} {β : αType u_2} (F : (a : α) → Equiv.Perm (β a)) (G : (a : α) → Equiv.Perm (β a)) :
                                                                                                @[simp]
                                                                                                theorem Equiv.Perm.sigmaCongrRight_symm {α : Type u_1} {β : αType u_2} (F : (a : α) → Equiv.Perm (β a)) :
                                                                                                (Equiv.Perm.sigmaCongrRight F).symm = Equiv.Perm.sigmaCongrRight fun (a : α) => (F a).symm
                                                                                                @[simp]
                                                                                                theorem Equiv.Perm.sigmaCongrRight_refl {α : Type u_1} {β : αType u_2} :
                                                                                                (Equiv.Perm.sigmaCongrRight fun (a : α) => Equiv.refl (β a)) = Equiv.refl ((a : α) × β a)
                                                                                                @[simp]
                                                                                                theorem Equiv.sigmaCongrLeft_apply {α₂ : Type u_1} {α₁ : Type u_2} {β : α₂Type u_3} (e : α₁ α₂) (a : (a : α₁) × β (e a)) :
                                                                                                (Equiv.sigmaCongrLeft e) a = { fst := e a.fst, snd := a.snd }
                                                                                                def Equiv.sigmaCongrLeft {α₂ : Type u_1} {α₁ : Type u_2} {β : α₂Type u_3} (e : α₁ α₂) :
                                                                                                (a : α₁) × β (e a) (a : α₂) × β a

                                                                                                An equivalence f : α₁ ≃ α₂ generates an equivalence between Σ a, β (f a) and Σ a, β a.

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                                                                                                • One or more equations did not get rendered due to their size.
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                                                                                                  def Equiv.sigmaCongrLeft' {α₁ : Type u_1} {α₂ : Type u_2} {β : α₁Type u_3} (f : α₁ α₂) :
                                                                                                  (a : α₁) × β a (a : α₂) × β (f.symm a)

                                                                                                  Transporting a sigma type through an equivalence of the base

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                                                                                                    def Equiv.sigmaCongr {α₁ : Type u_1} {α₂ : Type u_2} {β₁ : α₁Type u_3} {β₂ : α₂Type u_4} (f : α₁ α₂) (F : (a : α₁) → β₁ a β₂ (f a)) :
                                                                                                    Sigma β₁ Sigma β₂

                                                                                                    Transporting a sigma type through an equivalence of the base and a family of equivalences of matching fibers

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                                                                                                      @[simp]
                                                                                                      theorem Equiv.sigmaEquivProd_symm_apply (α : Type u_1) (β : Type u_2) (a : α × β) :
                                                                                                      (Equiv.sigmaEquivProd α β).symm a = { fst := a.fst, snd := a.snd }
                                                                                                      @[simp]
                                                                                                      theorem Equiv.sigmaEquivProd_apply (α : Type u_1) (β : Type u_2) (a : (_ : α) × β) :
                                                                                                      (Equiv.sigmaEquivProd α β) a = (a.fst, a.snd)
                                                                                                      def Equiv.sigmaEquivProd (α : Type u_1) (β : Type u_2) :
                                                                                                      (_ : α) × β α × β

                                                                                                      Sigma type with a constant fiber is equivalent to the product.

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                                                                                                      • Equiv.sigmaEquivProd α β = { toFun := fun (a : (_ : α) × β) => (a.fst, a.snd), invFun := fun (a : α × β) => { fst := a.fst, snd := a.snd }, left_inv := , right_inv := }
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                                                                                                        def Equiv.sigmaEquivProdOfEquiv {α : Type u_1} {β : Type u_2} {β₁ : αType u_3} (F : (a : α) → β₁ a β) :
                                                                                                        Sigma β₁ α × β

                                                                                                        If each fiber of a Sigma type is equivalent to a fixed type, then the sigma type is equivalent to the product.

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                                                                                                          def Equiv.sigmaAssoc {α : Type u_1} {β : αType u_2} (γ : (a : α) → β aType u_3) :
                                                                                                          (ab : (a : α) × β a) × γ ab.fst ab.snd (a : α) × (b : β a) × γ a b

                                                                                                          Dependent product of types is associative up to an equivalence.

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                                                                                                            theorem Equiv.exists_unique_congr {α : Sort u} {β : Sort v} {p : αProp} {q : βProp} (f : α β) (h : ∀ {x : α}, p x q (f x)) :
                                                                                                            (∃! (x : α), p x) ∃! (y : β), q y
                                                                                                            theorem Equiv.exists_unique_congr_left' {α : Sort u} {β : Sort v} {p : αProp} (f : α β) :
                                                                                                            (∃! (x : α), p x) ∃! (y : β), p (f.symm y)
                                                                                                            theorem Equiv.exists_unique_congr_left {α : Sort u} {β : Sort v} {p : βProp} (f : α β) :
                                                                                                            (∃! (x : α), p (f x)) ∃! (y : β), p y
                                                                                                            theorem Equiv.forall_congr {α : Sort u} {β : Sort v} {p : αProp} {q : βProp} (f : α β) (h : ∀ {x : α}, p x q (f x)) :
                                                                                                            (∀ (x : α), p x) ∀ (y : β), q y
                                                                                                            theorem Equiv.forall_congr' {α : Sort u} {β : Sort v} {p : αProp} {q : βProp} (f : α β) (h : ∀ {x : β}, p (f.symm x) q x) :
                                                                                                            (∀ (x : α), p x) ∀ (y : β), q y
                                                                                                            theorem Equiv.forall₂_congr {α₁ : Sort u_1} {β₁ : Sort u_2} {α₂ : Sort u_3} {β₂ : Sort u_4} {p : α₁β₁Prop} {q : α₂β₂Prop} (eα : α₁ α₂) (eβ : β₁ β₂) (h : ∀ {x : α₁} {y : β₁}, p x y q ( x) ( y)) :
                                                                                                            (∀ (x : α₁) (y : β₁), p x y) ∀ (x : α₂) (y : β₂), q x y
                                                                                                            theorem Equiv.forall₂_congr' {α₁ : Sort u_1} {β₁ : Sort u_2} {α₂ : Sort u_3} {β₂ : Sort u_4} {p : α₁β₁Prop} {q : α₂β₂Prop} (eα : α₁ α₂) (eβ : β₁ β₂) (h : ∀ {x : α₂} {y : β₂}, p (.symm x) (.symm y) q x y) :
                                                                                                            (∀ (x : α₁) (y : β₁), p x y) ∀ (x : α₂) (y : β₂), q x y
                                                                                                            theorem Equiv.forall₃_congr {α₁ : Sort u_1} {β₁ : Sort u_2} {γ₁ : Sort u_3} {α₂ : Sort u_4} {β₂ : Sort u_5} {γ₂ : Sort u_6} {p : α₁β₁γ₁Prop} {q : α₂β₂γ₂Prop} (eα : α₁ α₂) (eβ : β₁ β₂) (eγ : γ₁ γ₂) (h : ∀ {x : α₁} {y : β₁} {z : γ₁}, p x y z q ( x) ( y) ( z)) :
                                                                                                            (∀ (x : α₁) (y : β₁) (z : γ₁), p x y z) ∀ (x : α₂) (y : β₂) (z : γ₂), q x y z
                                                                                                            theorem Equiv.forall₃_congr' {α₁ : Sort u_1} {β₁ : Sort u_2} {γ₁ : Sort u_3} {α₂ : Sort u_4} {β₂ : Sort u_5} {γ₂ : Sort u_6} {p : α₁β₁γ₁Prop} {q : α₂β₂γ₂Prop} (eα : α₁ α₂) (eβ : β₁ β₂) (eγ : γ₁ γ₂) (h : ∀ {x : α₂} {y : β₂} {z : γ₂}, p (.symm x) (.symm y) (.symm z) q x y z) :
                                                                                                            (∀ (x : α₁) (y : β₁) (z : γ₁), p x y z) ∀ (x : α₂) (y : β₂) (z : γ₂), q x y z
                                                                                                            theorem Equiv.forall_congr_left' {α : Sort u} {β : Sort v} {p : αProp} (f : α β) :
                                                                                                            (∀ (x : α), p x) ∀ (y : β), p (f.symm y)
                                                                                                            theorem Equiv.forall_congr_left {α : Sort u} {β : Sort v} {p : βProp} (f : α β) :
                                                                                                            (∀ (x : α), p (f x)) ∀ (y : β), p y
                                                                                                            theorem Equiv.exists_congr_left {α : Sort u_1} {β : Sort u_2} (f : α β) {p : αProp} :
                                                                                                            (∃ (a : α), p a) ∃ (b : β), p (f.symm b)
                                                                                                            @[simp]
                                                                                                            theorem Equiv.ofBijective_apply {α : Sort u} {β : Sort v} (f : αβ) (hf : Function.Bijective f) :
                                                                                                            ∀ (a : α), (Equiv.ofBijective f hf) a = f a
                                                                                                            noncomputable def Equiv.ofBijective {α : Sort u} {β : Sort v} (f : αβ) (hf : Function.Bijective f) :
                                                                                                            α β

                                                                                                            If f is a bijective function, then its domain is equivalent to its codomain.

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                                                                                                              theorem Equiv.ofBijective_apply_symm_apply {α : Sort u} {β : Sort v} (f : αβ) (hf : Function.Bijective f) (x : β) :
                                                                                                              f ((Equiv.ofBijective f hf).symm x) = x
                                                                                                              @[simp]
                                                                                                              theorem Equiv.ofBijective_symm_apply_apply {α : Sort u} {β : Sort v} (f : αβ) (hf : Function.Bijective f) (x : α) :
                                                                                                              (Equiv.ofBijective f hf).symm (f x) = x
                                                                                                              def Quot.congr {α : Sort u} {β : Sort v} {ra : ααProp} {rb : ββProp} (e : α β) (eq : ∀ (a₁ a₂ : α), ra a₁ a₂ rb (e a₁) (e a₂)) :
                                                                                                              Quot ra Quot rb

                                                                                                              An equivalence e : α ≃ β generates an equivalence between quotient spaces, if ra a₁ a₂ ↔ rb (e a₁) (e a₂).

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                                                                                                                @[simp]
                                                                                                                theorem Quot.congr_mk {α : Sort u} {β : Sort v} {ra : ααProp} {rb : ββProp} (e : α β) (eq : ∀ (a₁ a₂ : α), ra a₁ a₂ rb (e a₁) (e a₂)) (a : α) :
                                                                                                                (Quot.congr e eq) (Quot.mk ra a) = Quot.mk rb (e a)
                                                                                                                def Quot.congrRight {α : Sort u} {r : ααProp} {r' : ααProp} (eq : ∀ (a₁ a₂ : α), r a₁ a₂ r' a₁ a₂) :

                                                                                                                Quotients are congruent on equivalences under equality of their relation. An alternative is just to use rewriting with eq, but then computational proofs get stuck.

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                                                                                                                  def Quot.congrLeft {α : Sort u} {β : Sort v} {r : ααProp} (e : α β) :
                                                                                                                  Quot r Quot fun (b b' : β) => r (e.symm b) (e.symm b')

                                                                                                                  An equivalence e : α ≃ β generates an equivalence between the quotient space of α by a relation ra and the quotient space of β by the image of this relation under e.

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                                                                                                                    def Quotient.congr {α : Sort u} {β : Sort v} {ra : Setoid α} {rb : Setoid β} (e : α β) (eq : ∀ (a₁ a₂ : α), Setoid.r a₁ a₂ Setoid.r (e a₁) (e a₂)) :

                                                                                                                    An equivalence e : α ≃ β generates an equivalence between quotient spaces, if ra a₁ a₂ ↔ rb (e a₁) (e a₂).

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                                                                                                                      @[simp]
                                                                                                                      theorem Quotient.congr_mk {α : Sort u} {β : Sort v} {ra : Setoid α} {rb : Setoid β} (e : α β) (eq : ∀ (a₁ a₂ : α), Setoid.r a₁ a₂ Setoid.r (e a₁) (e a₂)) (a : α) :
                                                                                                                      (Quotient.congr e eq) a = e a
                                                                                                                      def Quotient.congrRight {α : Sort u} {r : Setoid α} {r' : Setoid α} (eq : ∀ (a₁ a₂ : α), Setoid.r a₁ a₂ Setoid.r a₁ a₂) :

                                                                                                                      Quotients are congruent on equivalences under equality of their relation. An alternative is just to use rewriting with eq, but then computational proofs get stuck.

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