Search Results
Search type | Search syntax |
---|---|
Tags | [tag] |
Exact | "words here" |
Author |
user:1234 user:me (yours) |
Score |
score:3 (3+) score:0 (none) |
Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
Views | views:250 |
Code | code:"if (foo != bar)" |
Sections |
title:apples body:"apples oranges" |
URL | url:"*.example.com" |
Saves | in:saves |
Status |
closed:yes duplicate:no migrated:no wiki:no |
Types |
is:question is:answer |
Exclude |
-[tag] -apples |
For more details on advanced search visit our help page |
7
votes
Accepted
When are the zero sets of two continuous functions in the Stone-Čech compactification includ...
Lemma: Suppose that $X$ is a compact Hausdorff space. Let $f,g:X\rightarrow[0,\infty)$ be continuous functions. Then the following are equivalent:
$Z(f)\subseteq Z(g)$.
For all $\epsilon>0$, there e …
9
votes
Accepted
Sigma algebras on the Stone–Čech compactification of a countable discrete group
No.
First of all, take note that for compact zero-dimensional spaces $X$, the $\sigma$-algebra generated by all clopen sets is precisely the $\sigma$-algebra of Baire sets (recall that in a completel …
11
votes
Non-trivial convergent sequence in Stone-Čech compactification of $\mathbb{N}$
Let me give a fairly direct proof. Assume $R=(\mathcal{U}_{n})_{n}$ is a sequence of distinct ultrafilters on some set $X$. Since every infinite Hausdorff space has an infinite discrete subspace, ther …
7
votes
Non-trivial convergent sequence in Stone-Čech compactification of $\mathbb{N}$
This result follows from much stronger results from general topology. These results can be found in [1].
$\mathbf{Theorem}$ Each non-discrete closed subset of $\beta X\setminus\upsilon X$
conta …
17
votes
Accepted
Stone–Čech Compactification of $\mathbb{Z}$ with Fürstenberg Topology
We can also describe $\beta(\mathbb{Z},\mathcal{T})$ in terms of ultrafilters on Boolean algebras. I claim that $\beta(\mathbb{Z},\mathcal{T})$ is the space of ultrafilters on the Boolean algebra of c …