2
votes
1answer
99 views
Tensor product of C*-algebras of bounded, uniformly continuous functions on metric spaces
This is a follow up question to this one.
If $X$ is a metric space, denote by $C_u(X)$ the $C^\ast$-algebra of all bounded, uniformly continuous functions on $X$ (with the sup-nor …
2
votes
1answer
57 views
Extending uniformly continuous functions on subspaces to non-metrizable compactifications
I have a complete metric space $Y$, some non-metrizable(!) Hausdorff compactification $Z$ of it and a subspace $X \subset Y$.
Furthermore, I do have a uniformly continuous functio …
3
votes
2answers
144 views
For any entourage $U,V$ there’s an entourage $W$ such that $U\circ W\subseteq V\circ U$
Let $(X,\mathcal U)$ be a uniform space and let $U\in \mathcal U$. Is this statement true?
$$\forall V\in \mathcal U, \exists W\in \mathcal U, U\circ W\subseteq V\circ U$$
I think …
-2
votes
0answers
115 views
Is the topology generated by $\lbrace D[a] \mid a \in F \rbrace$ completely regular?
Suppose $(X,\mathcal D)$ is a precompact uniform space and $D\in \mathcal D$. there's a finite set $F\subseteq X$ such that
$$D[F]=X$$
Let $\mathcal T$ be the topology on $X$ gener …
1
vote
1answer
105 views
A uniformity with a countable base is a pseudometric uniformity.
I need a proof for this proposition:
If a uniformity $\mathfrak U$ on $X$ has a
countable fundamental system of
entourages, then it can be defined by
a pseudometric on $X …
3
votes
1answer
167 views
Does every proximal outer measure, measure all open sets?
Let $\: \langle X,\hspace{-0.015 in}\delta\hspace{.005 in}\rangle \:$ be a separated proximity space.
Let $\;\;\; \mu^* \: : \: 2^{\hspace{.01 in}X} \: \to \: \left[0,\hspace{-0.0 …
10
votes
2answers
274 views
Start with a topological group, take the meet of the two uniformities, and take the topology. Is the result again a topological group? [xpost from math.SE]
And what else can be said, if so?
(Original math.SE post)
In more detail: Say $(G,\mathscr{T})$ is a topological group. It has a left uniformity $\mathscr{L}$ and a right uniform …
1
vote
0answers
71 views
Collapse a closed subset of a uniform space.
I have proved that if you collapse a closed subset of a separated (Hausdorff) uniform space to a point, you get a separated uniform space. Surely such a simple result must be stan …
3
votes
3answers
316 views
Does every Lindelof uniform space have a Lindelof completion?
Recall Lindelof = every open cover has a countable subcover. Is the question of the title answered by known material from some standard text on uniform spaces?
Note it is well kn …
6
votes
4answers
790 views
Finite dimensional vector spaces over a complete but not-necessarily-valued field
I'm essentially reopening this old question of Ricky Demer which was never fully answered.
Essentially the original question: Suppose we have a topological field $F$ which is comp …
4
votes
1answer
212 views
Does the weak approximation theorem hold for general topological fields?
The weak approximation theorem states that given a field $F$ and nontrivial inequivalent absolute values $|\cdot|_1,\ldots,|\cdot|_n,$ and letting $F_i$ denote $F$ with the topolog …
2
votes
1answer
229 views
Chaos in uniform spaces
Let Dom be a uniform space, and f be a continuous function from Dom to itself satisfying:
(1)For all non-empty open subsets U and V of Dom, there exists a natural number n and a m …

