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toSubgroup_top : ((⊤ : OpenSubgroup G) : Subgroup G) = ⊤ := rfl @[to_additive (attr := simp, norm_cast)]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
toSubgroup_top
null
toOpens_top : ((⊤ : OpenSubgroup G) : Opens G) = ⊤ := rfl @[to_additive]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
toOpens_top
null
@[to_additive] isClosed [ContinuousMul G] (U : OpenSubgroup G) : IsClosed (U : Set G) := by apply isOpen_compl_iff.1 refine isOpen_iff_forall_mem_open.2 fun x hx ↦ ⟨(fun y ↦ y * x⁻¹) ⁻¹' U, ?_, ?_, ?_⟩ · refine fun u hux hu ↦ hx ?_ simp only [Set.mem_preimage, SetLike.mem_coe] at hux hu ⊢ convert U.mul_mem (U.inv_mem hux) hu simp · exact U.isOpen.preimage (continuous_mul_right _) · simp [one_mem] @[to_additive]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
isClosed
null
isClopen [ContinuousMul G] (U : OpenSubgroup G) : IsClopen (U : Set G) := ⟨U.isClosed, U.isOpen⟩
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
isClopen
null
@[to_additive prod /-- The product of two open subgroups as an open subgroup of the product group. -/] prod (U : OpenSubgroup G) (V : OpenSubgroup H) : OpenSubgroup (G × H) := ⟨.prod U V, U.isOpen.prod V.isOpen⟩ @[deprecated (since := "2025-03-11")] alias _root_.OpenAddSubgroup.sum := OpenAddSubgroup.prod @[to_additive (attr := simp, norm_cast) coe_prod]
def
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
prod
The product of two open subgroups as an open subgroup of the product group.
coe_prod (U : OpenSubgroup G) (V : OpenSubgroup H) : (U.prod V : Set (G × H)) = (U : Set G) ×ˢ (V : Set H) := rfl @[deprecated (since := "2025-03-11")] alias _root_.OpenAddSubgroup.coe_sum := OpenAddSubgroup.coe_prod @[to_additive (attr := simp, norm_cast) toAddSubgroup_prod]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
coe_prod
null
toSubgroup_prod (U : OpenSubgroup G) (V : OpenSubgroup H) : (U.prod V : Subgroup (G × H)) = (U : Subgroup G).prod V := rfl @[deprecated (since := "2025-03-11")] alias _root_.OpenAddSubgroup.toAddSubgroup_sum := OpenAddSubgroup.toAddSubgroup_prod
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
toSubgroup_prod
null
@[to_additive] instInfOpenSubgroup : Min (OpenSubgroup G) := ⟨fun U V ↦ ⟨U ⊓ V, U.isOpen.inter V.isOpen⟩⟩ @[to_additive (attr := simp, norm_cast)]
instance
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
instInfOpenSubgroup
null
coe_inf : (↑(U ⊓ V) : Set G) = (U : Set G) ∩ V := rfl @[to_additive (attr := simp, norm_cast)]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
coe_inf
null
toSubgroup_inf : (↑(U ⊓ V) : Subgroup G) = ↑U ⊓ ↑V := rfl @[to_additive (attr := simp, norm_cast)]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
toSubgroup_inf
null
toOpens_inf : (↑(U ⊓ V) : Opens G) = ↑U ⊓ ↑V := rfl @[to_additive (attr := simp)]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
toOpens_inf
null
mem_inf {x} : x ∈ U ⊓ V ↔ x ∈ U ∧ x ∈ V := Iff.rfl @[to_additive]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
mem_inf
null
instPartialOrderOpenSubgroup : PartialOrder (OpenSubgroup G) := inferInstance @[to_additive]
instance
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
instPartialOrderOpenSubgroup
null
instSemilatticeInfOpenSubgroup : SemilatticeInf (OpenSubgroup G) := { SetLike.coe_injective.semilatticeInf ((↑) : OpenSubgroup G → Set G) fun _ _ ↦ rfl with toPartialOrder := instPartialOrderOpenSubgroup } @[to_additive]
instance
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
instSemilatticeInfOpenSubgroup
null
@[to_additive (attr := simp, norm_cast)] toSubgroup_le : (U : Subgroup G) ≤ (V : Subgroup G) ↔ U ≤ V := Iff.rfl variable {N : Type*} [Group N] [TopologicalSpace N]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
toSubgroup_le
null
@[to_additive /-- The preimage of an `OpenAddSubgroup` along a continuous `AddMonoid` homomorphism is an `OpenAddSubgroup`. -/] comap (f : G →* N) (hf : Continuous f) (H : OpenSubgroup N) : OpenSubgroup G := ⟨.comap f H, H.isOpen.preimage hf⟩ @[to_additive (attr := simp, norm_cast)]
def
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
comap
The preimage of an `OpenSubgroup` along a continuous `Monoid` homomorphism is an `OpenSubgroup`.
coe_comap (H : OpenSubgroup N) (f : G →* N) (hf : Continuous f) : (H.comap f hf : Set G) = f ⁻¹' H := rfl @[to_additive (attr := simp, norm_cast)]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
coe_comap
null
toSubgroup_comap (H : OpenSubgroup N) (f : G →* N) (hf : Continuous f) : (H.comap f hf : Subgroup G) = (H : Subgroup N).comap f := rfl @[to_additive (attr := simp)]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
toSubgroup_comap
null
mem_comap {H : OpenSubgroup N} {f : G →* N} {hf : Continuous f} {x : G} : x ∈ H.comap f hf ↔ f x ∈ H := Iff.rfl @[to_additive]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
mem_comap
null
comap_comap {P : Type*} [Group P] [TopologicalSpace P] (K : OpenSubgroup P) (f₂ : N →* P) (hf₂ : Continuous f₂) (f₁ : G →* N) (hf₁ : Continuous f₁) : (K.comap f₂ hf₂).comap f₁ hf₁ = K.comap (f₂.comp f₁) (hf₂.comp hf₁) := rfl
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
comap_comap
null
@[to_additive] isOpen_of_mem_nhds [ContinuousMul G] (H : Subgroup G) {g : G} (hg : (H : Set G) ∈ 𝓝 g) : IsOpen (H : Set G) := by refine isOpen_iff_mem_nhds.2 fun x hx ↦ ?_ have hg' : g ∈ H := SetLike.mem_coe.1 (mem_of_mem_nhds hg) have : Filter.Tendsto (fun y ↦ y * (x⁻¹ * g)) (𝓝 x) (𝓝 g) := (continuous_id.mul continuous_const).tendsto' _ _ (mul_inv_cancel_left _ _) simpa only [SetLike.mem_coe, Filter.mem_map', H.mul_mem_cancel_right (H.mul_mem (H.inv_mem hx) hg')] using this hg @[to_additive]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
isOpen_of_mem_nhds
null
isOpen_mono [ContinuousMul G] {H₁ H₂ : Subgroup G} (h : H₁ ≤ H₂) (h₁ : IsOpen (H₁ : Set G)) : IsOpen (H₂ : Set G) := isOpen_of_mem_nhds _ <| Filter.mem_of_superset (h₁.mem_nhds <| one_mem H₁) h @[to_additive]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
isOpen_mono
null
isOpen_of_openSubgroup [ContinuousMul G] (H : Subgroup G) {U : OpenSubgroup G} (h : ↑U ≤ H) : IsOpen (H : Set G) := isOpen_mono h U.isOpen
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
isOpen_of_openSubgroup
null
@[to_additive /-- If a subgroup of an additive topological group has `0` in its interior, then it is open. -/] isOpen_of_one_mem_interior [ContinuousMul G] (H : Subgroup G) (h_1_int : (1 : G) ∈ interior (H : Set G)) : IsOpen (H : Set G) := isOpen_of_mem_nhds H <| mem_interior_iff_mem_nhds.1 h_1_int @[to_additive]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
isOpen_of_one_mem_interior
If a subgroup of a topological group has `1` in its interior, then it is open.
isClosed_of_isOpen [ContinuousMul G] (U : Subgroup G) (h : IsOpen (U : Set G)) : IsClosed (U : Set G) := OpenSubgroup.isClosed ⟨U, h⟩ @[to_additive]
lemma
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
isClosed_of_isOpen
null
subgroupOf_isOpen (U K : Subgroup G) (h : IsOpen (K : Set G)) : IsOpen (K.subgroupOf U : Set U) := Continuous.isOpen_preimage (continuous_iff_le_induced.mpr fun _ ↦ id) _ h @[to_additive]
lemma
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
subgroupOf_isOpen
null
discreteTopology [ContinuousMul G] (U : Subgroup G) (h : IsOpen (U : Set G)) : DiscreteTopology (G ⧸ U) := by refine singletons_open_iff_discrete.mp (fun g ↦ ?_) induction g using Quotient.inductionOn with | h g => change IsOpen (QuotientGroup.mk ⁻¹' {QuotientGroup.mk g}) convert_to IsOpen ((g * ·) '' U) · ext g' simp only [Set.mem_preimage, Set.mem_singleton_iff, QuotientGroup.eq, Set.image_mul_left] rw [← U.inv_mem_iff] simp · exact Homeomorph.mulLeft g |>.isOpen_image |>.mpr h @[to_additive]
lemma
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
discreteTopology
null
@[to_additive] quotient_finite_of_isOpen [ContinuousMul G] [CompactSpace G] (U : Subgroup G) (h : IsOpen (U : Set G)) : Finite (G ⧸ U) := have : DiscreteTopology (G ⧸ U) := U.discreteTopology h finite_of_compact_of_discrete @[to_additive]
lemma
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
quotient_finite_of_isOpen
null
@[to_additive] quotient_finite_of_isOpen' [IsTopologicalGroup G] [CompactSpace G] (U : Subgroup G) (K : Subgroup U) (hUopen : IsOpen (U : Set G)) (hKopen : IsOpen (K : Set U)) : Finite (U ⧸ K) := have : CompactSpace U := isCompact_iff_compactSpace.mp <| IsClosed.isCompact <| U.isClosed_of_isOpen hUopen K.quotient_finite_of_isOpen hKopen @[to_additive]
lemma
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
quotient_finite_of_isOpen'
null
@[to_additive (attr := simp, norm_cast)] toSubgroup_sup (U V : OpenSubgroup G) : (↑(U ⊔ V) : Subgroup G) = ↑U ⊔ ↑V := rfl @[to_additive]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
toSubgroup_sup
null
isOpen_mono {U P : Submodule R M} (h : U ≤ P) (hU : IsOpen (U : Set M)) : IsOpen (P : Set M) := @AddSubgroup.isOpen_mono M _ _ _ U.toAddSubgroup P.toAddSubgroup h hU
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
isOpen_mono
null
isOpen_of_isOpen_subideal {U I : Ideal R} (h : U ≤ I) (hU : IsOpen (U : Set R)) : IsOpen (I : Set R) := @Submodule.isOpen_mono R R _ _ _ _ Semiring.toModule _ _ h hU
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
isOpen_of_isOpen_subideal
null
@[ext] OpenNormalSubgroup (G : Type u) [Group G] [TopologicalSpace G] extends OpenSubgroup G where isNormal' : toSubgroup.Normal := by infer_instance
structure
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
OpenNormalSubgroup
The type of open normal subgroups of a topological group.
@[ext] OpenNormalAddSubgroup (G : Type u) [AddGroup G] [TopologicalSpace G] extends OpenAddSubgroup G where isNormal' : toAddSubgroup.Normal := by infer_instance attribute [to_additive] OpenNormalSubgroup
structure
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
OpenNormalAddSubgroup
The type of open normal subgroups of a topological additive group.
@[to_additive] toSubgroup_injective : Function.Injective (fun H ↦ H.toOpenSubgroup.toSubgroup : OpenNormalSubgroup G → Subgroup G) := fun A B h ↦ by ext dsimp at h rw [h] @[to_additive]
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
toSubgroup_injective
null
@[to_additive] instPartialOrderOpenNormalSubgroup : PartialOrder (OpenNormalSubgroup G) := inferInstance @[to_additive]
instance
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
instPartialOrderOpenNormalSubgroup
null
instInfOpenNormalSubgroup : Min (OpenNormalSubgroup G) := ⟨fun U V ↦ ⟨U.toOpenSubgroup ⊓ V.toOpenSubgroup, Subgroup.normal_inf_normal U.toSubgroup V.toSubgroup⟩⟩ @[to_additive]
instance
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
instInfOpenNormalSubgroup
null
instSemilatticeInfOpenNormalSubgroup : SemilatticeInf (OpenNormalSubgroup G) := SetLike.coe_injective.semilatticeInf ((↑) : OpenNormalSubgroup G → Set G) fun _ _ ↦ rfl @[to_additive]
instance
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
instSemilatticeInfOpenNormalSubgroup
null
@[to_additive] instSemilatticeSupOpenNormalSubgroup [ContinuousMul G] : SemilatticeSup (OpenNormalSubgroup G) := toSubgroup_injective.semilatticeSup _ (fun _ _ ↦ rfl) @[to_additive]
instance
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
instSemilatticeSupOpenNormalSubgroup
null
IsTopologicalAddGroup.addNegClosureNhd (T W : Set G) [AddGroup G] : Prop where nhds : T ∈ 𝓝 0 neg : -T = T isOpen : IsOpen T add : W + T ⊆ W
structure
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
IsTopologicalAddGroup.addNegClosureNhd
null
@[to_additive /-- For a set `W`, `T` is a neighborhood of `0` which is open, stable under negation and satisfies `T + W ⊆ W`. -/] IsTopologicalGroup.mulInvClosureNhd (T W : Set G) [Group G] : Prop where nhds : T ∈ 𝓝 1 inv : T⁻¹ = T isOpen : IsOpen T mul : W * T ⊆ W
structure
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
IsTopologicalGroup.mulInvClosureNhd
For a set `W`, `T` is a neighborhood of `1` which is open, stable under inverse and satisfies `T * W ⊆ W`.
@[to_additive] exist_mul_closure_nhds {W : Set G} (WClopen : IsClopen W) : ∃ T ∈ 𝓝 (1 : G), W * T ⊆ W := by apply WClopen.isClosed.isCompact.induction_on (p := fun S ↦ ∃ T ∈ 𝓝 (1 : G), S * T ⊆ W) ⟨Set.univ, by simp only [univ_mem, empty_mul, empty_subset, and_self]⟩ (fun _ _ huv ⟨T, hT, mem⟩ ↦ ⟨T, hT, (mul_subset_mul_right huv).trans mem⟩) fun U V ⟨T₁, hT₁, mem1⟩ ⟨T₂, hT₂, mem2⟩ ↦ ⟨T₁ ∩ T₂, inter_mem hT₁ hT₂, by rw [union_mul] exact union_subset (mul_subset_mul_left inter_subset_left |>.trans mem1) (mul_subset_mul_left inter_subset_right |>.trans mem2) ⟩ intro x memW have : (x, 1) ∈ (fun p ↦ p.1 * p.2) ⁻¹' W := by simp [memW] rcases isOpen_prod_iff.mp (continuous_mul.isOpen_preimage W <| WClopen.2) x 1 this with ⟨U, V, Uopen, Vopen, xmemU, onememV, prodsub⟩ have h6 : U * V ⊆ W := mul_subset_iff.mpr (fun _ hx _ hy ↦ prodsub (mk_mem_prod hx hy)) exact ⟨U ∩ W, ⟨U, Uopen.mem_nhds xmemU, W, fun _ a ↦ a, rfl⟩, V, IsOpen.mem_nhds Vopen onememV, fun _ a ↦ h6 ((mul_subset_mul_right inter_subset_left) a)⟩ @[deprecated (since := "2025-05-22")] alias exist_mul_closure_nhd := exist_mul_closure_nhds @[deprecated (since := "2025-05-22")] alias _root_.IsTopologicalAddGroup.exist_add_closure_nhd := IsTopologicalAddGroup.exist_add_closure_nhds @[to_additive]
lemma
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
exist_mul_closure_nhds
null
exists_mulInvClosureNhd {W : Set G} (WClopen : IsClopen W) : ∃ T, mulInvClosureNhd T W := by rcases exist_mul_closure_nhds WClopen with ⟨S, Smemnhds, mulclose⟩ rcases mem_nhds_iff.mp Smemnhds with ⟨U, UsubS, Uopen, onememU⟩ use U ∩ U⁻¹ constructor · simp [Uopen.mem_nhds onememU, inv_mem_nhds_one] · simp [inter_comm] · exact Uopen.inter Uopen.inv · exact fun a ha ↦ mulclose (mul_subset_mul_left UsubS (mul_subset_mul_left inter_subset_left ha)) @[to_additive]
lemma
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
exists_mulInvClosureNhd
null
exist_openSubgroup_sub_clopen_nhds_of_one {G : Type*} [Group G] [TopologicalSpace G] [IsTopologicalGroup G] [CompactSpace G] {W : Set G} (WClopen : IsClopen W) (einW : 1 ∈ W) : ∃ H : OpenSubgroup G, (H : Set G) ⊆ W := by rcases exists_mulInvClosureNhd WClopen with ⟨V, hV⟩ let S : Subgroup G := { carrier := ⋃ n, V ^ (n + 1) mul_mem' := fun ha hb ↦ by rcases mem_iUnion.mp ha with ⟨k, hk⟩ rcases mem_iUnion.mp hb with ⟨l, hl⟩ apply mem_iUnion.mpr use k + 1 + l rw [add_assoc, pow_add] exact Set.mul_mem_mul hk hl one_mem' := by apply mem_iUnion.mpr use 0 simp [mem_of_mem_nhds hV.nhds] inv_mem' := fun ha ↦ by rcases mem_iUnion.mp ha with ⟨k, hk⟩ apply mem_iUnion.mpr use k rw [← hV.inv] simpa only [inv_pow, Set.mem_inv, inv_inv] using hk } have : IsOpen (⋃ n, V ^ (n + 1)) := by refine isOpen_iUnion (fun n ↦ ?_) rw [pow_succ] exact hV.isOpen.mul_left use ⟨S, this⟩ have mulVpow (n : ℕ) : W * V ^ (n + 1) ⊆ W := by induction n with | zero => simp [hV.mul] | succ n ih => rw [pow_succ, ← mul_assoc] exact (Set.mul_subset_mul_right ih).trans hV.mul have (n : ℕ) : V ^ (n + 1) ⊆ W * V ^ (n + 1) := by intro x xin rw [Set.mem_mul] use 1, einW, x, xin rw [one_mul] apply iUnion_subset fun i _ a ↦ mulVpow i (this i a) @[deprecated (since := "2025-05-22")] alias exist_openSubgroup_sub_clopen_nhd_of_one := exist_openSubgroup_sub_clopen_nhds_of_one @[deprecated (since := "2025-05-22")] alias _root_.IsTopologicalAddGroup.exist_openAddSubgroup_sub_clopen_nhd_of_zero := IsTopologicalAddGroup.exist_openAddSubgroup_sub_clopen_nhds_of_zero
theorem
Topology
[ "Mathlib.Algebra.Module.Submodule.Lattice", "Mathlib.RingTheory.Ideal.Defs", "Mathlib.Topology.Algebra.Group.Quotient", "Mathlib.Topology.Algebra.Ring.Basic", "Mathlib.Topology.Sets.Opens" ]
Mathlib/Topology/Algebra/OpenSubgroup.lean
exist_openSubgroup_sub_clopen_nhds_of_one
null
@[continuity, fun_prop] protected continuous_eval₂ [Semiring S] (p : S[X]) (f : S →+* R) : Continuous fun x => p.eval₂ f x := by simp only [eval₂_eq_sum] exact continuous_finset_sum _ fun c _ => continuous_const.mul (continuous_pow _) @[continuity, fun_prop]
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
continuous_eval₂
null
protected continuous : Continuous fun x => p.eval x := p.continuous_eval₂ _ @[fun_prop]
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
continuous
null
protected continuousAt {a : R} : ContinuousAt (fun x => p.eval x) a := p.continuous.continuousAt @[fun_prop]
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
continuousAt
null
protected continuousWithinAt {s a} : ContinuousWithinAt (fun x => p.eval x) s a := p.continuous.continuousWithinAt @[fun_prop]
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
continuousWithinAt
null
protected continuousOn {s} : ContinuousOn (fun x => p.eval x) s := p.continuous.continuousOn
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
continuousOn
null
@[continuity, fun_prop] protected continuous_aeval : Continuous fun x : A => aeval x p := p.continuous_eval₂ _ @[fun_prop]
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
continuous_aeval
null
protected continuousAt_aeval {a : A} : ContinuousAt (fun x : A => aeval x p) a := p.continuous_aeval.continuousAt @[fun_prop]
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
continuousAt_aeval
null
protected continuousWithinAt_aeval {s a} : ContinuousWithinAt (fun x : A => aeval x p) s a := p.continuous_aeval.continuousWithinAt @[fun_prop]
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
continuousWithinAt_aeval
null
protected continuousOn_aeval {s} : ContinuousOn (fun x : A => aeval x p) s := p.continuous_aeval.continuousOn
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
continuousOn_aeval
null
tendsto_abv_eval₂_atTop {R S k α : Type*} [Semiring R] [Ring S] [Field k] [LinearOrder k] [IsStrictOrderedRing k] (f : R →+* S) (abv : S → k) [IsAbsoluteValue abv] (p : R[X]) (hd : 0 < degree p) (hf : f p.leadingCoeff ≠ 0) {l : Filter α} {z : α → S} (hz : Tendsto (abv ∘ z) l atTop) : Tendsto (fun x => abv (p.eval₂ f (z x))) l atTop := by revert hf; refine degree_pos_induction_on p hd ?_ ?_ ?_ <;> clear hd p · rintro _ - hc rw [leadingCoeff_mul_X, leadingCoeff_C] at hc simpa [abv_mul abv] using hz.const_mul_atTop ((abv_pos abv).2 hc) · intro _ _ ihp hf rw [leadingCoeff_mul_X] at hf simpa [abv_mul abv] using (ihp hf).atTop_mul_atTop₀ hz · intro _ a hd ihp hf rw [add_comm, leadingCoeff_add_of_degree_lt (degree_C_le.trans_lt hd)] at hf refine .atTop_of_add_const (abv (-f a)) ?_ refine tendsto_atTop_mono (fun _ => abv_add abv _ _) ?_ simpa using ihp hf
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
tendsto_abv_eval₂_atTop
null
tendsto_abv_atTop {R k α : Type*} [Ring R] [Field k] [LinearOrder k] [IsStrictOrderedRing k] (abv : R → k) [IsAbsoluteValue abv] (p : R[X]) (h : 0 < degree p) {l : Filter α} {z : α → R} (hz : Tendsto (abv ∘ z) l atTop) : Tendsto (fun x => abv (p.eval (z x))) l atTop := by apply tendsto_abv_eval₂_atTop _ _ _ h _ hz exact mt leadingCoeff_eq_zero.1 (ne_zero_of_degree_gt h)
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
tendsto_abv_atTop
null
tendsto_abv_aeval_atTop {R A k α : Type*} [CommSemiring R] [Ring A] [Algebra R A] [Field k] [LinearOrder k] [IsStrictOrderedRing k] (abv : A → k) [IsAbsoluteValue abv] (p : R[X]) (hd : 0 < degree p) (h₀ : algebraMap R A p.leadingCoeff ≠ 0) {l : Filter α} {z : α → A} (hz : Tendsto (abv ∘ z) l atTop) : Tendsto (fun x => abv (aeval (z x) p)) l atTop := tendsto_abv_eval₂_atTop _ abv p hd h₀ hz variable {α R : Type*} [NormedRing R] [IsAbsoluteValue (norm : R → ℝ)]
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
tendsto_abv_aeval_atTop
null
tendsto_norm_atTop (p : R[X]) (h : 0 < degree p) {l : Filter α} {z : α → R} (hz : Tendsto (fun x => ‖z x‖) l atTop) : Tendsto (fun x => ‖p.eval (z x)‖) l atTop := p.tendsto_abv_atTop norm h hz
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
tendsto_norm_atTop
null
exists_forall_norm_le [ProperSpace R] (p : R[X]) : ∃ x, ∀ y, ‖p.eval x‖ ≤ ‖p.eval y‖ := if hp0 : 0 < degree p then p.continuous.norm.exists_forall_le <| p.tendsto_norm_atTop hp0 tendsto_norm_cocompact_atTop else ⟨p.coeff 0, by rw [eq_C_of_degree_le_zero (le_of_not_gt hp0)]; simp⟩
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
exists_forall_norm_le
null
eq_one_of_roots_le {p : F[X]} {f : F →+* K} {B : ℝ} (hB : B < 0) (h1 : p.Monic) (h2 : Splits f p) (h3 : ∀ z ∈ (map f p).roots, ‖z‖ ≤ B) : p = 1 := h1.natDegree_eq_zero_iff_eq_one.mp (by contrapose! hB rw [← h1.natDegree_map f, natDegree_eq_card_roots' h2] at hB obtain ⟨z, hz⟩ := card_pos_iff_exists_mem.mp (zero_lt_iff.mpr hB) exact le_trans (norm_nonneg _) (h3 z hz))
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
eq_one_of_roots_le
null
coeff_le_of_roots_le {p : F[X]} {f : F →+* K} {B : ℝ} (i : ℕ) (h1 : p.Monic) (h2 : Splits f p) (h3 : ∀ z ∈ (map f p).roots, ‖z‖ ≤ B) : ‖(map f p).coeff i‖ ≤ B ^ (p.natDegree - i) * p.natDegree.choose i := by obtain hB | hB := lt_or_ge B 0 · rw [eq_one_of_roots_le hB h1 h2 h3, Polynomial.map_one, natDegree_one, zero_tsub, pow_zero, one_mul, coeff_one] split_ifs with h <;> simp [h] rw [← h1.natDegree_map f] obtain hi | hi := lt_or_ge (map f p).natDegree i · rw [coeff_eq_zero_of_natDegree_lt hi, norm_zero] positivity rw [coeff_eq_esymm_roots_of_splits ((splits_id_iff_splits f).2 h2) hi, (h1.map _).leadingCoeff, one_mul, norm_mul, norm_pow, norm_neg, norm_one, one_pow, one_mul] apply ((norm_multiset_sum_le _).trans <| sum_le_card_nsmul _ _ fun r hr => _).trans · rw [Multiset.map_map, card_map, card_powersetCard, ← natDegree_eq_card_roots' h2, Nat.choose_symm hi, mul_comm, nsmul_eq_mul] intro r hr simp_rw [Multiset.mem_map] at hr obtain ⟨_, ⟨s, hs, rfl⟩, rfl⟩ := hr rw [mem_powersetCard] at hs lift B to ℝ≥0 using hB rw [← coe_nnnorm, ← NNReal.coe_pow, NNReal.coe_le_coe, ← nnnormHom_apply, ← MonoidHom.coe_coe, MonoidHom.map_multiset_prod] refine (prod_le_pow_card _ B fun x hx => ?_).trans_eq (by rw [card_map, hs.2]) obtain ⟨z, hz, rfl⟩ := Multiset.mem_map.1 hx exact h3 z (mem_of_le hs.1 hz)
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
coeff_le_of_roots_le
null
coeff_bdd_of_roots_le {B : ℝ} {d : ℕ} (f : F →+* K) {p : F[X]} (h1 : p.Monic) (h2 : Splits f p) (h3 : p.natDegree ≤ d) (h4 : ∀ z ∈ (map f p).roots, ‖z‖ ≤ B) (i : ℕ) : ‖(map f p).coeff i‖ ≤ max B 1 ^ d * d.choose (d / 2) := by obtain hB | hB := le_or_gt 0 B · apply (coeff_le_of_roots_le i h1 h2 h4).trans calc _ ≤ max B 1 ^ (p.natDegree - i) * p.natDegree.choose i := by gcongr; apply le_max_left _ ≤ max B 1 ^ d * p.natDegree.choose i := by gcongr · apply le_max_right · exact le_trans (Nat.sub_le _ _) h3 _ ≤ max B 1 ^ d * d.choose (d / 2) := by gcongr; exact (i.choose_mono h3).trans (i.choose_le_middle d) · rw [eq_one_of_roots_le hB h1 h2 h4, Polynomial.map_one, coeff_one] refine le_trans ?_ (one_le_mul_of_one_le_of_one_le (one_le_pow₀ (le_max_right B 1)) ?_) · split_ifs <;> norm_num · exact mod_cast Nat.succ_le_iff.mpr (Nat.choose_pos (d.div_le_self 2))
theorem
Topology
[ "Mathlib.Algebra.Polynomial.AlgebraMap", "Mathlib.Algebra.Polynomial.Inductions", "Mathlib.Algebra.Polynomial.Splits", "Mathlib.RingTheory.Polynomial.Vieta", "Mathlib.Analysis.Normed.Field.Basic", "Mathlib.Analysis.Normed.Ring.Lemmas" ]
Mathlib/Topology/Algebra/Polynomial.lean
coeff_bdd_of_roots_le
The coefficients of the monic polynomials of bounded degree with bounded roots are uniformly bounded.
PontryaginDual := A →ₜ* Circle deriving TopologicalSpace
def
Topology
[ "Mathlib.Analysis.SpecialFunctions.Complex.Circle", "Mathlib.Topology.Algebra.Group.CompactOpen" ]
Mathlib/Topology/Algebra/PontryaginDual.lean
PontryaginDual
The Pontryagin dual of `A` is the group of continuous homomorphism `A → Circle`.
map (f : A →ₜ* B) : (PontryaginDual B) →ₜ* (PontryaginDual A) := f.compLeft Circle @[simp]
def
Topology
[ "Mathlib.Analysis.SpecialFunctions.Complex.Circle", "Mathlib.Topology.Algebra.Group.CompactOpen" ]
Mathlib/Topology/Algebra/PontryaginDual.lean
map
A discrete monoid has compact Pontryagin dual. -/ add_decl_doc instLocallyCompactSpacePontryaginDual /-- `PontryaginDual` is a contravariant functor.
map_apply (f : A →ₜ* B) (x : PontryaginDual B) (y : A) : map f x y = x (f y) := rfl @[simp]
theorem
Topology
[ "Mathlib.Analysis.SpecialFunctions.Complex.Circle", "Mathlib.Topology.Algebra.Group.CompactOpen" ]
Mathlib/Topology/Algebra/PontryaginDual.lean
map_apply
null
map_one : map (1 : A →ₜ* B) = 1 := ext fun x => ext (fun _y => OneHomClass.map_one x) @[simp]
theorem
Topology
[ "Mathlib.Analysis.SpecialFunctions.Complex.Circle", "Mathlib.Topology.Algebra.Group.CompactOpen" ]
Mathlib/Topology/Algebra/PontryaginDual.lean
map_one
null
map_comp (g : B →ₜ* C) (f : A →ₜ* B) : map (comp g f) = ContinuousMonoidHom.comp (map f) (map g) := ext fun _x => ext fun _y => rfl @[simp] nonrec theorem map_mul (f g : A →ₜ* G) : map (f * g) = map f * map g := ext fun x => ext fun y => map_mul x (f y) (g y) variable (A B C G)
theorem
Topology
[ "Mathlib.Analysis.SpecialFunctions.Complex.Circle", "Mathlib.Topology.Algebra.Group.CompactOpen" ]
Mathlib/Topology/Algebra/PontryaginDual.lean
map_comp
null
mapHom [LocallyCompactSpace G] : (A →ₜ* G) →ₜ* ((PontryaginDual G) →ₜ* (PontryaginDual A)) where toFun := map map_one' := map_one map_mul' := map_mul continuous_toFun := continuous_of_continuous_uncurry _ continuous_comp
def
Topology
[ "Mathlib.Analysis.SpecialFunctions.Complex.Circle", "Mathlib.Topology.Algebra.Group.CompactOpen" ]
Mathlib/Topology/Algebra/PontryaginDual.lean
mapHom
`ContinuousMonoidHom.dual` as a `ContinuousMonoidHom`.
ProperConstVAdd (M X : Type*) [VAdd M X] [TopologicalSpace X] : Prop where /-- `(c +ᵥ ·)` is a proper map. -/ isProperMap_vadd (c : M) : IsProperMap ((c +ᵥ ·) : X → X)
class
Topology
[ "Mathlib.Topology.Algebra.ConstMulAction", "Mathlib.Topology.Maps.Proper.Basic" ]
Mathlib/Topology/Algebra/ProperConstSMul.lean
ProperConstVAdd
A mixin typeclass saying that the `(c +ᵥ ·)` is a proper map for all `c`. Note that this is **not** the same as a proper additive action (not yet in `Mathlib`).
@[to_additive] ProperConstSMul (M X : Type*) [SMul M X] [TopologicalSpace X] : Prop where /-- `(c • ·)` is a proper map. -/ isProperMap_smul (c : M) : IsProperMap ((c • ·) : X → X)
class
Topology
[ "Mathlib.Topology.Algebra.ConstMulAction", "Mathlib.Topology.Maps.Proper.Basic" ]
Mathlib/Topology/Algebra/ProperConstSMul.lean
ProperConstSMul
A mixin typeclass saying that `(c • ·)` is a proper map for all `c`. Note that this is **not** the same as a proper multiplicative action (not yet in `Mathlib`).
@[to_additive /-- `(c +ᵥ ·)` is a proper map. -/] isProperMap_smul {M : Type*} (c : M) (X : Type*) [SMul M X] [TopologicalSpace X] [h : ProperConstSMul M X] : IsProperMap ((c • ·) : X → X) := h.1 c
theorem
Topology
[ "Mathlib.Topology.Algebra.ConstMulAction", "Mathlib.Topology.Maps.Proper.Basic" ]
Mathlib/Topology/Algebra/ProperConstSMul.lean
isProperMap_smul
`(c • ·)` is a proper map.
@[to_additive /-- The preimage of a compact set under `(c +ᵥ ·)` is a compact set. -/] IsCompact.preimage_smul {M X : Type*} [SMul M X] [TopologicalSpace X] [ProperConstSMul M X] {s : Set X} (hs : IsCompact s) (c : M) : IsCompact ((c • ·) ⁻¹' s) := (isProperMap_smul c X).isCompact_preimage hs @[to_additive]
theorem
Topology
[ "Mathlib.Topology.Algebra.ConstMulAction", "Mathlib.Topology.Maps.Proper.Basic" ]
Mathlib/Topology/Algebra/ProperConstSMul.lean
IsCompact.preimage_smul
The preimage of a compact set under `(c • ·)` is a compact set.
@[to_additive /-- Any nonempty compact Hausdorff additive semigroup where right-addition is continuous contains an idempotent, i.e. an `m` such that `m + m = m` -/] exists_idempotent_of_compact_t2_of_continuous_mul_left {M} [Nonempty M] [Semigroup M] [TopologicalSpace M] [CompactSpace M] [T2Space M] (continuous_mul_left : ∀ r : M, Continuous (· * r)) : ∃ m : M, m * m = m := by /- We apply Zorn's lemma to the poset of nonempty closed subsemigroups of `M`. It will turn out that any minimal element is `{m}` for an idempotent `m : M`. -/ let S : Set (Set M) := { N | IsClosed N ∧ N.Nonempty ∧ ∀ (m) (_ : m ∈ N) (m') (_ : m' ∈ N), m * m' ∈ N } rsuffices ⟨N, hN⟩ : ∃ N', Minimal (· ∈ S) N' · obtain ⟨N_closed, ⟨m, hm⟩, N_mul⟩ := hN.prop use m /- We now have an element `m : M` of a minimal subsemigroup `N`, and want to show `m + m = m`. We first show that every element of `N` is of the form `m' + m`. -/ have scaling_eq_self : (· * m) '' N = N := by apply hN.eq_of_subset · refine ⟨(continuous_mul_left m).isClosedMap _ N_closed, ⟨_, ⟨m, hm, rfl⟩⟩, ?_⟩ rintro _ ⟨m'', hm'', rfl⟩ _ ⟨m', hm', rfl⟩ exact ⟨m'' * m * m', N_mul _ (N_mul _ hm'' _ hm) _ hm', mul_assoc _ _ _⟩ · rintro _ ⟨m', hm', rfl⟩ exact N_mul _ hm' _ hm /- In particular, this means that `m' * m = m` for some `m'`. We now use minimality again to show that this holds for all `m' ∈ N`. -/ have absorbing_eq_self : N ∩ { m' | m' * m = m } = N := by apply hN.eq_of_subset · refine ⟨N_closed.inter ((T1Space.t1 m).preimage (continuous_mul_left m)), ?_, ?_⟩ · rwa [← scaling_eq_self] at hm · rintro m'' ⟨mem'', eq'' : _ = m⟩ m' ⟨mem', eq' : _ = m⟩ refine ⟨N_mul _ mem'' _ mem', ?_⟩ rw [Set.mem_setOf_eq, mul_assoc, eq', eq''] apply Set.inter_subset_left rw [← absorbing_eq_self] at hm exact hm.2 refine zorn_superset _ fun c hcs hc => ?_ refine ⟨⋂₀ c, ⟨isClosed_sInter fun t ht => (hcs ht).1, ?_, fun m hm m' hm' => ?_⟩, fun s hs => Set.sInter_subset_of_mem hs⟩ · obtain rfl | hcnemp := c.eq_empty_or_nonempty · rw [Set.sInter_empty] apply Set.univ_nonempty convert @IsCompact.nonempty_iInter_of_directed_nonempty_isCompact_isClosed _ _ _ hcnemp.coe_sort ((↑) : c → Set M) ?_ ?_ ?_ ?_ · exact Set.sInter_eq_iInter · refine DirectedOn.directed_val (IsChain.directedOn hc.symm) exacts [fun i => (hcs i.prop).2.1, fun i => (hcs i.prop).1.isCompact, fun i => (hcs i.prop).1] · rw [Set.mem_sInter] exact fun t ht => (hcs ht).2.2 m (Set.mem_sInter.mp hm t ht) m' (Set.mem_sInter.mp hm' t ht)
theorem
Topology
[ "Mathlib.Algebra.Group.Defs", "Mathlib.Topology.Separation.Hausdorff" ]
Mathlib/Topology/Algebra/Semigroup.lean
exists_idempotent_of_compact_t2_of_continuous_mul_left
Any nonempty compact Hausdorff semigroup where right-multiplication is continuous contains an idempotent, i.e. an `m` such that `m * m = m`.
@[to_additive exists_idempotent_in_compact_add_subsemigroup /-- A version of `exists_idempotent_of_compact_t2_of_continuous_add_left` where the idempotent lies in some specified nonempty compact additive subsemigroup. -/] exists_idempotent_in_compact_subsemigroup {M} [Semigroup M] [TopologicalSpace M] [T2Space M] (continuous_mul_left : ∀ r : M, Continuous (· * r)) (s : Set M) (snemp : s.Nonempty) (s_compact : IsCompact s) (s_add : ∀ᵉ (x ∈ s) (y ∈ s), x * y ∈ s) : ∃ m ∈ s, m * m = m := by let M' := { m // m ∈ s } letI : Semigroup M' := { mul := fun p q => ⟨p.1 * q.1, s_add _ p.2 _ q.2⟩ mul_assoc := fun p q r => Subtype.eq (mul_assoc _ _ _) } haveI : CompactSpace M' := isCompact_iff_compactSpace.mp s_compact haveI : Nonempty M' := nonempty_subtype.mpr snemp have : ∀ p : M', Continuous (· * p) := fun p => ((continuous_mul_left p.1).comp continuous_subtype_val).subtype_mk _ obtain ⟨⟨m, hm⟩, idem⟩ := exists_idempotent_of_compact_t2_of_continuous_mul_left this exact ⟨m, hm, Subtype.ext_iff.mp idem⟩
theorem
Topology
[ "Mathlib.Algebra.Group.Defs", "Mathlib.Topology.Separation.Hausdorff" ]
Mathlib/Topology/Algebra/Semigroup.lean
exists_idempotent_in_compact_subsemigroup
A version of `exists_idempotent_of_compact_t2_of_continuous_mul_left` where the idempotent lies in some specified nonempty compact subsemigroup.
ContinuousStar (R : Type*) [TopologicalSpace R] [Star R] : Prop where /-- The `star` operator is continuous. -/ continuous_star : Continuous (star : R → R) export ContinuousStar (continuous_star)
class
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
ContinuousStar
Basic hypothesis to talk about a topological space with a continuous `star` operator.
continuousOn_star {s : Set R} : ContinuousOn star s := continuous_star.continuousOn
theorem
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
continuousOn_star
null
continuousWithinAt_star {s : Set R} {x : R} : ContinuousWithinAt star s x := continuous_star.continuousWithinAt
theorem
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
continuousWithinAt_star
null
continuousAt_star {x : R} : ContinuousAt star x := continuous_star.continuousAt
theorem
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
continuousAt_star
null
tendsto_star (a : R) : Tendsto star (𝓝 a) (𝓝 (star a)) := continuousAt_star
theorem
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
tendsto_star
null
Filter.Tendsto.star {f : α → R} {l : Filter α} {y : R} (h : Tendsto f l (𝓝 y)) : Tendsto (fun x => star (f x)) l (𝓝 (star y)) := (continuous_star.tendsto y).comp h variable [TopologicalSpace α] {f : α → R} {s : Set α} {x : α} @[continuity, fun_prop]
theorem
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
Filter.Tendsto.star
null
Continuous.star (hf : Continuous f) : Continuous fun x => star (f x) := continuous_star.comp hf @[fun_prop]
theorem
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
Continuous.star
null
ContinuousAt.star (hf : ContinuousAt f x) : ContinuousAt (fun x => star (f x)) x := continuousAt_star.comp hf @[fun_prop]
theorem
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
ContinuousAt.star
null
ContinuousOn.star (hf : ContinuousOn f s) : ContinuousOn (fun x => star (f x)) s := continuous_star.comp_continuousOn hf
theorem
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
ContinuousOn.star
null
ContinuousWithinAt.star (hf : ContinuousWithinAt f s x) : ContinuousWithinAt (fun x => star (f x)) s x := Filter.Tendsto.star hf
theorem
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
ContinuousWithinAt.star
null
@[simps] starContinuousMap : C(R, R) := ⟨star, continuous_star⟩
def
Topology
[ "Mathlib.Topology.Algebra.Constructions", "Mathlib.Topology.ContinuousMap.Defs", "Mathlib.Algebra.Star.Basic" ]
Mathlib/Topology/Algebra/Star.lean
starContinuousMap
The star operation bundled as a continuous map.
isEmbedding_inclusion {S₁ S₂ : StarSubalgebra R A} (h : S₁ ≤ S₂) : IsEmbedding (inclusion h) where eq_induced := Eq.symm induced_compose injective := Subtype.map_injective h Function.injective_id
lemma
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
isEmbedding_inclusion
The `StarSubalgebra.inclusion` of a star subalgebra is an embedding.
isClosedEmbedding_inclusion {S₁ S₂ : StarSubalgebra R A} (h : S₁ ≤ S₂) (hS₁ : IsClosed (S₁ : Set A)) : IsClosedEmbedding (inclusion h) := { IsEmbedding.inclusion h with isClosed_range := isClosed_induced_iff.2 ⟨S₁, hS₁, by convert (Set.range_subtype_map id _).symm · rw [Set.image_id]; rfl · intro _ h' apply h h' ⟩ } variable [IsTopologicalSemiring A] [ContinuousStar A] variable [TopologicalSpace B] [Semiring B] [Algebra R B] [StarRing B]
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
isClosedEmbedding_inclusion
The `StarSubalgebra.inclusion` of a closed star subalgebra is a `IsClosedEmbedding`.
topologicalClosure (s : StarSubalgebra R A) : StarSubalgebra R A := { s.toSubalgebra.topologicalClosure with carrier := closure (s : Set A) star_mem' := fun ha => map_mem_closure continuous_star ha fun x => (star_mem : x ∈ s → star x ∈ s) }
def
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
topologicalClosure
The closure of a star subalgebra in a topological star algebra as a star subalgebra.
topologicalClosure_toSubalgebra_comm (s : StarSubalgebra R A) : s.topologicalClosure.toSubalgebra = s.toSubalgebra.topologicalClosure := SetLike.coe_injective rfl @[simp]
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
topologicalClosure_toSubalgebra_comm
null
topologicalClosure_coe (s : StarSubalgebra R A) : (s.topologicalClosure : Set A) = closure (s : Set A) := rfl
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
topologicalClosure_coe
null
le_topologicalClosure (s : StarSubalgebra R A) : s ≤ s.topologicalClosure := subset_closure
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
le_topologicalClosure
null
isClosed_topologicalClosure (s : StarSubalgebra R A) : IsClosed (s.topologicalClosure : Set A) := isClosed_closure
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
isClosed_topologicalClosure
null
topologicalClosure_minimal {s t : StarSubalgebra R A} (h : s ≤ t) (ht : IsClosed (t : Set A)) : s.topologicalClosure ≤ t := closure_minimal h ht
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
topologicalClosure_minimal
null
topologicalClosure_mono : Monotone (topologicalClosure : _ → StarSubalgebra R A) := fun _ S₂ h => topologicalClosure_minimal (h.trans <| le_topologicalClosure S₂) (isClosed_topologicalClosure S₂)
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
topologicalClosure_mono
null
topologicalClosure_map_le [StarModule R B] [IsTopologicalSemiring B] [ContinuousStar B] (s : StarSubalgebra R A) (φ : A →⋆ₐ[R] B) (hφ : IsClosedMap φ) : (map φ s).topologicalClosure ≤ map φ s.topologicalClosure := hφ.closure_image_subset _
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
topologicalClosure_map_le
null
map_topologicalClosure_le [StarModule R B] [IsTopologicalSemiring B] [ContinuousStar B] (s : StarSubalgebra R A) (φ : A →⋆ₐ[R] B) (hφ : Continuous φ) : map φ s.topologicalClosure ≤ (map φ s).topologicalClosure := image_closure_subset_closure_image hφ
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
map_topologicalClosure_le
null
topologicalClosure_map [StarModule R B] [IsTopologicalSemiring B] [ContinuousStar B] (s : StarSubalgebra R A) (φ : A →⋆ₐ[R] B) (hφ : IsClosedMap φ) (hφ' : Continuous φ) : (map φ s).topologicalClosure = map φ s.topologicalClosure := SetLike.coe_injective <| hφ.closure_image_eq_of_continuous hφ' _ variable (R) in open StarAlgebra in
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
topologicalClosure_map
null
topologicalClosure_adjoin_le_centralizer_centralizer [T2Space A] (s : Set A) : (adjoin R s).topologicalClosure ≤ centralizer R (centralizer R s) := topologicalClosure_minimal (adjoin_le_centralizer_centralizer R s) (Set.isClosed_centralizer _)
lemma
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
topologicalClosure_adjoin_le_centralizer_centralizer
null
_root_.Subalgebra.topologicalClosure_star_comm (s : Subalgebra R A) : (star s).topologicalClosure = star s.topologicalClosure := by suffices ∀ t : Subalgebra R A, (star t).topologicalClosure ≤ star t.topologicalClosure from le_antisymm (this s) (by simpa only [star_star] using Subalgebra.star_mono (this (star s))) exact fun t => (star t).topologicalClosure_minimal (Subalgebra.star_mono subset_closure) (isClosed_closure.preimage continuous_star)
theorem
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
_root_.Subalgebra.topologicalClosure_star_comm
null
commSemiringTopologicalClosure [T2Space A] (s : StarSubalgebra R A) (hs : ∀ x y : s, x * y = y * x) : CommSemiring s.topologicalClosure := s.toSubalgebra.commSemiringTopologicalClosure hs
abbrev
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
commSemiringTopologicalClosure
If a star subalgebra of a topological star algebra is commutative, then so is its topological closure. See note [reducible non-instances].
commRingTopologicalClosure {R A} [CommRing R] [StarRing R] [TopologicalSpace A] [Ring A] [Algebra R A] [StarRing A] [StarModule R A] [IsTopologicalRing A] [ContinuousStar A] [T2Space A] (s : StarSubalgebra R A) (hs : ∀ x y : s, x * y = y * x) : CommRing s.topologicalClosure := s.toSubalgebra.commRingTopologicalClosure hs
abbrev
Topology
[ "Mathlib.Algebra.Star.Subalgebra", "Mathlib.Topology.Algebra.Algebra", "Mathlib.Topology.Algebra.Star" ]
Mathlib/Topology/Algebra/StarSubalgebra.lean
commRingTopologicalClosure
If a star subalgebra of a topological star algebra is commutative, then so is its topological closure. See note [reducible non-instances].