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 | |
Results tagged with tag-removed
Search options not deleted
user 10909
This tag is to be used only when re-tagging highly(!) off-topic questions where none of the actual tags would make sense; all actual tags the questioner has used are removed and something is needed to have some tag, which is enforced by the software, so this tag is used. However note that this tag is also used in the process of moderators deleting tags. Thus a question having this tag does most of the time not mean that somebody found it off-topic.
4
votes
On Pseudo-finite topological spaces
I believe you can grow your example B into a counterexample.
Stage 0 is $\emptyset$
Stage 1 is $\{p\}$.
Stage 2 is your $B$: you've added a copy of ${\Bbb N}$ for each point newly added in the pre …
- 17.6k
0
votes
On Pseudo-finite topological spaces
The counterexamples so far depend on AC, but one can have such spaces just from ZF.
In particular, instead of an ultrafilter on ${\Bbb N}$ as in your example $B$, one can use the filter of subsets wi …
- 17.6k
1
vote
Accepted
On One point Lindeloffication of topological spaces
As for $Q_2$, take $X \times S^1$ with $X$ discrete. The one-point Lindeloffication follows along the same lines as above. Of course any one-point compactification is a fortiori a
one-point Lindelof …
- 17.6k
2
votes
What is the simplest, most elementary proof that a particular number is transcendental?
Full details require a short paper rather than a long MO comment and Daniel Briggs and I have started discussing writing one jointly. But let me address some of what you ask right now.
A finite coll …
- 17.6k
31
votes
What is the simplest, most elementary proof that a particular number is transcendental?
I keep meaning to write this up nicely, but one can prove the transcendentality of Liouville's number in a very, very elementary way.
Write $L$ for the Liouville number. Suppose $p(L)=0$ for some p …
- 17.6k