Uniform embeddings of uniform spaces. #
Extension of uniform continuous functions.
Uniform inducing maps #
A map f : α → β
between uniform spaces is called uniform inducing if the uniformity filter
on α
is the pullback of the uniformity filter on β
under Prod.map f f
. If α
is a separated
space, then this implies that f
is injective, hence it is a IsUniformEmbedding
.
- comap_uniformity : Filter.comap (fun (x : α × α) => (f x.1, f x.2)) (uniformity β) = uniformity α
The uniformity filter on the domain is the pullback of the uniformity filter on the codomain under
Prod.map f f
.
Instances For
The uniformity filter on the domain is the pullback of the uniformity filter on the codomain
under Prod.map f f
.
Alias of the forward direction of uniformInducing_iff_uniformSpace
.
Uniform embeddings #
A map f : α → β
between uniform spaces is a uniform embedding if it is uniform inducing and
injective. If α
is a separated space, then the latter assumption follows from the former.
- comap_uniformity : Filter.comap (fun (x : α × α) => (f x.1, f x.2)) (uniformity β) = uniformity α
- inj : Function.Injective f
A uniform embedding is injective.
Instances For
A uniform embedding is injective.
Alias of IsUniformEmbedding
.
A map f : α → β
between uniform spaces is a uniform embedding if it is uniform inducing and
injective. If α
is a separated space, then the latter assumption follows from the former.
Equations
Instances For
Alias of isUniformEmbedding_iff'
.
Alias of Filter.HasBasis.isUniformEmbedding_iff'
.
Alias of Filter.HasBasis.isUniformEmbedding_iff
.
Alias of isUniformEmbedding_subtype_val
.
Alias of isUniformEmbedding_set_inclusion
.
Alias of IsUniformEmbedding.comp
.
Alias of IsUniformEmbedding.of_comp_iff
.
Alias of Equiv.isUniformEmbedding
.
Alias of isUniformEmbedding_inl
.
Alias of isUniformEmbedding_inr
.
If the domain of a UniformInducing
map f
is a T₀ space, then f
is injective,
hence it is a IsUniformEmbedding
.
Alias of UniformInducing.isUniformEmbedding
.
If the domain of a UniformInducing
map f
is a T₀ space, then f
is injective,
hence it is a IsUniformEmbedding
.
Alias of isUniformEmbedding_iff_uniformInducing
.
If a map f : α → β
sends any two distinct points to point that are not related by a fixed
s ∈ 𝓤 β
, then f
is uniform inducing with respect to the discrete uniformity on α
:
the preimage of 𝓤 β
under Prod.map f f
is the principal filter generated by the diagonal in
α × α
.
If a map f : α → β
sends any two distinct points to point that are not related by a fixed
s ∈ 𝓤 β
, then f
is a uniform embedding with respect to the discrete uniformity on α
.
Alias of isUniformEmbedding_of_spaced_out
.
If a map f : α → β
sends any two distinct points to point that are not related by a fixed
s ∈ 𝓤 β
, then f
is a uniform embedding with respect to the discrete uniformity on α
.
Alias of IsUniformEmbedding.embedding
.
Alias of IsUniformEmbedding.isDenseEmbedding
.
Alias of IsUniformEmbedding.isDenseEmbedding
.
Alias of isUniformEmbedding_subtypeEmb
.
Alias of IsUniformEmbedding.prod
.
A set is complete iff its image under a uniform inducing map is complete.
If f : X → Y
is an UniformInducing
map, the image f '' s
of a set s
is complete
if and only if s
is complete.
If f : X → Y
is an IsUniformEmbedding
, the image f '' s
of a set s
is complete
if and only if s
is complete.
Alias of IsUniformEmbedding.isComplete_iff
.
If f : X → Y
is an IsUniformEmbedding
, the image f '' s
of a set s
is complete
if and only if s
is complete.
Sets of a subtype are complete iff their image under the coercion is complete.
Alias of the forward direction of isComplete_image_iff
.
A set is complete iff its image under a uniform inducing map is complete.
Alias of the reverse direction of completeSpace_iff_isComplete_range
.
If f
is a surjective uniform inducing map,
then its domain is a complete space iff its codomain is a complete space.
See also _root_.completeSpace_congr
for a version that assumes f
to be an equivalence.
Equations
- ⋯ = ⋯
See also UniformInducing.completeSpace_congr
for a version that works for non-injective maps.
Alias of the reverse direction of completeSpace_coe_iff_isComplete
.
The lift of a complete space to another universe is still complete.
Equations
- ⋯ = ⋯
Equations
- ⋯ = ⋯
Alias of isUniformEmbedding_comap
.
Pull back a uniform space structure by an embedding, adjusting the new uniform structure to make sure that its topology is defeq to the original one.
Equations
- Embedding.comapUniformSpace f h = (UniformSpace.comap f u).replaceTopology ⋯
Instances For
Alias of Embedding.to_isUniformEmbedding
.