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Mathlib.Topology.Algebra.Constructions

Topological space structure on the opposite monoid and on the units group #

In this file we define TopologicalSpace structure on Mᵐᵒᵖ, Mᵃᵒᵖ, , and AddUnits M. This file does not import definitions of a topological monoid and/or a continuous multiplicative action, so we postpone the proofs of ContinuousMul Mᵐᵒᵖ etc. till we have these definitions.

Tags #

topological space, opposite monoid, units

@[implicit_reducible]

Put the same topological space structure on the opposite monoid as on the original space.

@[implicit_reducible]

Put the same topological space structure on the opposite monoid as on the original space.

@[simp]
theorem AddOpposite.opHomeomorph_apply {M : Type u_1} [TopologicalSpace M] (a✝ : M) :
opHomeomorph a✝ = op a✝
@[simp]
theorem MulOpposite.opHomeomorph_apply {M : Type u_1} [TopologicalSpace M] (a✝ : M) :
opHomeomorph a✝ = op a✝
@[simp]
theorem MulOpposite.map_op_nhds {M : Type u_1} [TopologicalSpace M] (x : M) :
@[simp]
theorem AddOpposite.map_op_nhds {M : Type u_1} [TopologicalSpace M] (x : M) :
@[implicit_reducible]

The units of a monoid are equipped with a topology, via the embedding into M × M.

@[implicit_reducible]

The additive units of a monoid are equipped with a topology, via the embedding into M × M.

theorem Units.isEmbedding_val_mk' {M : Type u_4} [Monoid M] [TopologicalSpace M] {f : MM} (hc : ContinuousOn f {x : M | IsUnit x}) (hf : ∀ (u : Mˣ), f u = u⁻¹) :

An auxiliary lemma that can be used to prove that coercion Mˣ → M is a topological embedding. Use Units.isEmbedding_val₀, Units.isEmbedding_val, or toUnits_homeomorph instead.

theorem AddUnits.isEmbedding_val_mk' {M : Type u_4} [AddMonoid M] [TopologicalSpace M] {f : MM} (hc : ContinuousOn f {x : M | IsAddUnit x}) (hf : ∀ (u : AddUnits M), f u = ↑(-u)) :

An auxiliary lemma that can be used to prove that coercion AddUnits M → M is a topological embedding. Use AddUnits.isEmbedding_val or toAddUnits_homeomorph instead.

An auxiliary lemma that can be used to prove that coercion Mˣ → M is a topological embedding. Use Units.isEmbedding_val₀, Units.isEmbedding_val, or toUnits_homeomorph instead.

An auxiliary lemma that can be used to prove that coercion AddUnits M → M is a topological embedding. Use AddUnits.isEmbedding_val or toAddUnits_homeomorph instead.

theorem Units.continuous_iff {M : Type u_1} {X : Type u_3} [TopologicalSpace M] [Monoid M] [TopologicalSpace X] {f : XMˣ} :
Continuous f Continuous (val f) Continuous fun (x : X) => (f x)⁻¹
theorem AddUnits.continuous_iff {M : Type u_1} {X : Type u_3} [TopologicalSpace M] [AddMonoid M] [TopologicalSpace X] {f : XAddUnits M} :
Continuous f Continuous (val f) Continuous fun (x : X) => ↑(-f x)
theorem Units.continuous_map {M : Type u_1} {N : Type u_2} [TopologicalSpace M] [Monoid M] [TopologicalSpace N] [Monoid N] {f : M →* N} (hf : Continuous f) :
theorem AddUnits.continuous_map {M : Type u_1} {N : Type u_2} [TopologicalSpace M] [AddMonoid M] [TopologicalSpace N] [AddMonoid N] {f : M →+ N} (hf : Continuous f) :
theorem Units.isOpenMap_map {M : Type u_1} {N : Type u_2} [TopologicalSpace M] [Monoid M] [TopologicalSpace N] [Monoid N] {f : M →* N} (hf_inj : Function.Injective f) (hf : IsOpenMap f) :
IsOpenMap (map f)
theorem AddUnits.isOpenMap_map {M : Type u_1} {N : Type u_2} [TopologicalSpace M] [AddMonoid M] [TopologicalSpace N] [AddMonoid N] {f : M →+ N} (hf_inj : Function.Injective f) (hf : IsOpenMap f) :
IsOpenMap (map f)