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Mathlib.Topology.Covering.Quotient

Covering maps to quotients by free and properly discontinuous group actions #

structure IsAddQuotientCoveringMap {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] (f : E β†’ X) (G : Type u_4) [AddGroup G] [AddAction G E] extends Topology.IsQuotientMap f, ContinuousConstVAdd G E :

A function from a topological space E with an action by a discrete group to another topological space X is a quotient covering map if it is a quotient map, the action is continuous and transitive on fibers, and every point of E has a neighborhood whose translates by the group elements are pairwise disjoint.

Instances For
    structure IsQuotientCoveringMap {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] (f : E β†’ X) (G : Type u_3) [Group G] [MulAction G E] extends Topology.IsQuotientMap f, ContinuousConstSMul G E :

    A function from a topological space E with an action by a discrete group to another topological space X is a quotient covering map if it is a quotient map, the action is continuous and transitive on fibers, and every point of E has a neighborhood whose translates by the group elements are pairwise disjoint.

    Instances For
      theorem isQuotientCoveringMap_iff {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] (f : E β†’ X) (G : Type u_3) [Group G] [MulAction G E] :
      IsQuotientCoveringMap f G ↔ Topology.IsQuotientMap f ∧ ContinuousConstSMul G E ∧ (βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ MulAction.orbit G eβ‚‚) ∧ βˆ€ (e : E), βˆƒ U ∈ nhds e, βˆ€ (g : G), ((fun (x : E) => g β€’ x) '' U ∩ U).Nonempty β†’ g = 1
      theorem isAddQuotientCoveringMap_iff {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] (f : E β†’ X) (G : Type u_3) [AddGroup G] [AddAction G E] :
      IsAddQuotientCoveringMap f G ↔ Topology.IsQuotientMap f ∧ ContinuousConstVAdd G E ∧ (βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ AddAction.orbit G eβ‚‚) ∧ βˆ€ (e : E), βˆƒ U ∈ nhds e, βˆ€ (g : G), ((fun (x : E) => g +α΅₯ x) '' U ∩ U).Nonempty β†’ g = 0
      theorem IsQuotientCoveringMap.subgroup_congr {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] (f : E β†’ X) (G : Type u_3) [Group G] [MulAction G E] (S S' : Subgroup G) (eq : S = S') :
      theorem IsAddQuotientCoveringMap.addSubgroup_congr {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] (f : E β†’ X) (G : Type u_3) [AddGroup G] [AddAction G E] (S S' : AddSubgroup G) (eq : S = S') :
      theorem IsQuotientCoveringMap.isCancelSMul {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] (f : E β†’ X) (G : Type u_3) [Group G] [MulAction G E] (h : IsQuotientCoveringMap f G) :

      The group action on the domain of a quotient covering map is free.

      theorem IsQuotientCoveringMap.homeomorph_comp {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [Group G] [MulAction G E] (h : IsQuotientCoveringMap f G) {Y : Type u_4} [TopologicalSpace Y] (Ο† : X β‰ƒβ‚œ Y) :
      IsQuotientCoveringMap (⇑φ ∘ f) G
      theorem IsAddQuotientCoveringMap.homeomorph_comp {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [AddGroup G] [AddAction G E] (h : IsAddQuotientCoveringMap f G) {Y : Type u_4} [TopologicalSpace Y] (Ο† : X β‰ƒβ‚œ Y) :
      @[simp]
      theorem IsQuotientCoveringMap.homeomorph_comp_iff {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [Group G] [MulAction G E] {Y : Type u_4} [TopologicalSpace Y] (Ο† : X β‰ƒβ‚œ Y) :
      noncomputable def Topology.IsQuotientMap.trivializationOfSMulDisjoint {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [Group G] [MulAction G E] (hf : IsQuotientMap f) [ContinuousConstSMul G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ MulAction.orbit G eβ‚‚) [TopologicalSpace G] [DiscreteTopology G] (U : Set E) (open_U : IsOpen U) (disjoint : βˆ€ (g : G), ((fun (x : E) => g β€’ x) '' U ∩ U).Nonempty β†’ g = 1) :

      If a group G acts on a space E and U is an open subset disjoint from all other G-translates of itself, and p is a quotient map by this action, then p admits a Trivialization over the base set p(U).

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          noncomputable def Topology.IsQuotientMap.trivializationOfVAddDisjoint {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [AddGroup G] [AddAction G E] (hf : IsQuotientMap f) [ContinuousConstVAdd G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ AddAction.orbit G eβ‚‚) [TopologicalSpace G] [DiscreteTopology G] (U : Set E) (open_U : IsOpen U) (disjoint : βˆ€ (g : G), ((fun (x : E) => g +α΅₯ x) '' U ∩ U).Nonempty β†’ g = 0) :

          If a group G acts on a space E and U is an open subset disjoint from all other G-translates of itself, and p is a quotient map by this action, then p admits a Trivialization over the base set p(U).

          Equations
            Instances For
              @[simp]
              theorem Topology.IsQuotientMap.trivializationOfVAddDisjoint_target {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [AddGroup G] [AddAction G E] (hf : IsQuotientMap f) [ContinuousConstVAdd G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ AddAction.orbit G eβ‚‚) [TopologicalSpace G] [DiscreteTopology G] (U : Set E) (open_U : IsOpen U) (disjoint : βˆ€ (g : G), ((fun (x : E) => g +α΅₯ x) '' U ∩ U).Nonempty β†’ g = 0) :
              (hf.trivializationOfVAddDisjoint hfG U open_U disjoint).target = (f '' U) Γ—Λ’ Set.univ
              @[simp]
              theorem Topology.IsQuotientMap.trivializationOfSMulDisjoint_source {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [Group G] [MulAction G E] (hf : IsQuotientMap f) [ContinuousConstSMul G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ MulAction.orbit G eβ‚‚) [TopologicalSpace G] [DiscreteTopology G] (U : Set E) (open_U : IsOpen U) (disjoint : βˆ€ (g : G), ((fun (x : E) => g β€’ x) '' U ∩ U).Nonempty β†’ g = 1) :
              (hf.trivializationOfSMulDisjoint hfG U open_U disjoint).source = f ⁻¹' (f '' U)
              @[simp]
              theorem Topology.IsQuotientMap.trivializationOfVAddDisjoint_baseSet {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [AddGroup G] [AddAction G E] (hf : IsQuotientMap f) [ContinuousConstVAdd G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ AddAction.orbit G eβ‚‚) [TopologicalSpace G] [DiscreteTopology G] (U : Set E) (open_U : IsOpen U) (disjoint : βˆ€ (g : G), ((fun (x : E) => g +α΅₯ x) '' U ∩ U).Nonempty β†’ g = 0) :
              (hf.trivializationOfVAddDisjoint hfG U open_U disjoint).baseSet = f '' U
              @[simp]
              theorem Topology.IsQuotientMap.trivializationOfVAddDisjoint_source {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [AddGroup G] [AddAction G E] (hf : IsQuotientMap f) [ContinuousConstVAdd G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ AddAction.orbit G eβ‚‚) [TopologicalSpace G] [DiscreteTopology G] (U : Set E) (open_U : IsOpen U) (disjoint : βˆ€ (g : G), ((fun (x : E) => g +α΅₯ x) '' U ∩ U).Nonempty β†’ g = 0) :
              (hf.trivializationOfVAddDisjoint hfG U open_U disjoint).source = f ⁻¹' (f '' U)
              @[simp]
              theorem Topology.IsQuotientMap.trivializationOfSMulDisjoint_target {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [Group G] [MulAction G E] (hf : IsQuotientMap f) [ContinuousConstSMul G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ MulAction.orbit G eβ‚‚) [TopologicalSpace G] [DiscreteTopology G] (U : Set E) (open_U : IsOpen U) (disjoint : βˆ€ (g : G), ((fun (x : E) => g β€’ x) '' U ∩ U).Nonempty β†’ g = 1) :
              (hf.trivializationOfSMulDisjoint hfG U open_U disjoint).target = (f '' U) Γ—Λ’ Set.univ
              @[simp]
              theorem Topology.IsQuotientMap.trivializationOfSMulDisjoint_baseSet {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [Group G] [MulAction G E] (hf : IsQuotientMap f) [ContinuousConstSMul G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ MulAction.orbit G eβ‚‚) [TopologicalSpace G] [DiscreteTopology G] (U : Set E) (open_U : IsOpen U) (disjoint : βˆ€ (g : G), ((fun (x : E) => g β€’ x) '' U ∩ U).Nonempty β†’ g = 1) :
              (hf.trivializationOfSMulDisjoint hfG U open_U disjoint).baseSet = f '' U
              theorem Topology.IsQuotientMap.isCoveringMapOn_of_smul_disjoint {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [Group G] [MulAction G E] (hf : IsQuotientMap f) [ContinuousConstSMul G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ MulAction.orbit G eβ‚‚) (disjoint : βˆ€ (e : E), βˆƒ U ∈ nhds e, βˆ€ (g : G), ((fun (x : E) => g β€’ x) '' U ∩ U).Nonempty β†’ g β€’ e = e) :
              theorem Topology.IsQuotientMap.isCoveringMapOn_of_vadd_disjoint {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [AddGroup G] [AddAction G E] (hf : IsQuotientMap f) [ContinuousConstVAdd G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ AddAction.orbit G eβ‚‚) (disjoint : βˆ€ (e : E), βˆƒ U ∈ nhds e, βˆ€ (g : G), ((fun (x : E) => g +α΅₯ x) '' U ∩ U).Nonempty β†’ g +α΅₯ e = e) :
              theorem Topology.IsQuotientMap.isCoveringMapOn_of_properlyDiscontinuousSMul {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [Group G] [MulAction G E] (hf : IsQuotientMap f) [ContinuousConstSMul G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ MulAction.orbit G eβ‚‚) [ProperlyDiscontinuousSMul G E] [LocallyCompactSpace E] [T2Space E] :
              theorem Topology.IsQuotientMap.isCoveringMapOn_of_properlyDiscontinuousVAdd {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [AddGroup G] [AddAction G E] (hf : IsQuotientMap f) [ContinuousConstVAdd G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ AddAction.orbit G eβ‚‚) [ProperlyDiscontinuousVAdd G E] [LocallyCompactSpace E] [T2Space E] :
              theorem Topology.IsQuotientMap.isQuotientCoveringMap_of_properlyDiscontinuousSMul {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [Group G] [MulAction G E] (hf : IsQuotientMap f) [ContinuousConstSMul G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ MulAction.orbit G eβ‚‚) [ProperlyDiscontinuousSMul G E] [LocallyCompactSpace E] [T2Space E] [IsCancelSMul G E] :
              theorem Topology.IsQuotientMap.isAddQuotientCoveringMap_of_properlyDiscontinuousVAdd {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} {G : Type u_3} [AddGroup G] [AddAction G E] (hf : IsQuotientMap f) [ContinuousConstVAdd G E] (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ AddAction.orbit G eβ‚‚) [ProperlyDiscontinuousVAdd G E] [LocallyCompactSpace E] [T2Space E] [IsCancelVAdd G E] :
              theorem Topology.IsQuotientMap.isQuotientCoveringMap_of_subgroup {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} (hf : IsQuotientMap f) [Group E] [IsTopologicalGroup E] (G : Subgroup E) (hG : IsDiscrete ↑G) (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ eβ‚‚ * e₁⁻¹ ∈ G) :
              theorem Topology.IsQuotientMap.isAddQuotientCoveringMap_of_addSubgroup {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} (hf : IsQuotientMap f) [AddGroup E] [IsTopologicalAddGroup E] (G : AddSubgroup E) (hG : IsDiscrete ↑G) (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ eβ‚‚ + -e₁ ∈ G) :
              theorem Topology.IsQuotientMap.isQuotientCoveringMap_of_subgroupOp {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} (hf : IsQuotientMap f) [Group E] [IsTopologicalGroup E] (G : Subgroup E) (hG : IsDiscrete ↑G) (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁⁻¹ * eβ‚‚ ∈ G) :
              theorem Topology.IsQuotientMap.isAddQuotientCoveringMap_of_addSubgroupOp {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] {f : E β†’ X} (hf : IsQuotientMap f) [AddGroup E] [IsTopologicalAddGroup E] (G : AddSubgroup E) (hG : IsDiscrete ↑G) (hfG : βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ -e₁ + eβ‚‚ ∈ G) :
              theorem isQuotientCoveringMap_iff_isCoveringMap_and {E : Type u_1} {X : Type u_2} [TopologicalSpace E] [TopologicalSpace X] (f : E β†’ X) (G : Type u_3) [Group G] [MulAction G E] :
              IsQuotientCoveringMap f G ↔ IsCoveringMap f ∧ Function.Surjective f ∧ ContinuousConstSMul G E ∧ IsCancelSMul G E ∧ βˆ€ {e₁ eβ‚‚ : E}, f e₁ = f eβ‚‚ ↔ e₁ ∈ MulAction.orbit G eβ‚‚