Skip to main content
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
Search options questions only not deleted user 1441

Topology of cell complexes and manifolds, classification of manifolds (e.g. smoothing, surgery), low dimensional topology (e.g. knot theory, invariants of 4-manifolds), embedding theory, combinatorial and PL topology, geometric group theory, infinite dimensional topology (e.g. Hilbert cube manifolds, theory of retracts).

24 votes
4 answers
4k views

Fundamental group of 3-manifold with boundary

Is it true that any finitely presented group can be realized as fundamental group of compact 3-manifold with boundary?
3 votes
1 answer
322 views

Simplified Bing's house

Bing's house is an example of contractible 2-complex in $\mathbb{R}^3$. One may think that it is a surface without boundary that has two types of singularities: tripod curves — curves where three piec …
6 votes
1 answer
301 views

Stable torus that is not a torus [duplicate]

Let $M$ be a closed manifold such that $M\times \mathbb{S}^1$ is a torus. Is it true that $M$ is homeomorphic to a torus?
13 votes
1 answer
562 views

Limit of homeomorphisms from square to square

Let $\square=[0,1]\times[0,1]$ be the unit square and $f\colon\square\to \square$ is a continuous map that fixes the points on the boundary. Assume $f$ is a limit of homeomorphisms $\square\to \squar …
18 votes
2 answers
1k views

Which immersed plane curves bound an immersed disk?

I am looking for a nice answer to the following question. Which immersed plane curves bound an immersed disk? Comments. I am not sure what is a nice answer, but for sure I could make a stupid …
16 votes
2 answers
813 views

Klee's trick --- more applications

In his "Some topological properties..." (1955), Klee gave a construction (simple and beautiful) of an isotopy $h_t\colon\mathbb{R}^{2\cdot n}\to \mathbb{R}^{2\cdot n}$ which moves any compact set $K$ …
17 votes
1 answer
573 views

Simply connected slices

Assume $\Omega$ is an open set in $\mathbb R^3$ such that the intersection of $\Omega$ with any horizontal plane is simply connected. Can you prove that $\Omega$ is simply connected? (Note th …
13 votes
1 answer
861 views

Ramified cover of 4-sphere

Is it true that any closed oriented $4$-dimensional manifold can be obtained as a result of the following construction: Take $S^4$ with a finite collection of immersed closed 2-manifolds (with trans …
10 votes
1 answer
387 views

Wild half-line in a Euclidean space

Is there an $m$-dimensional simplicial complex $S$ with the following properties: The cone over $S$ is homeomorphic to $\mathbb{E}^{m+1}$. Here $\mathbb{E}^{m+1}$ denoes the $(m+1)$-dimensional Eucl …
15 votes
1 answer
410 views

bi-Lipschitz gluing

Let $H$ be the Heisenberg group with left invariant sub-Riemannian metric and $\varepsilon>0$ is small. Let us denote by $|x-y|_H$ the distance from $x$ to $y$ in $H$. I have a bi-Lipschitz homeomor …
20 votes
2 answers
1k views

Rugged manifold

It is well known that any compact smooth $m$-manifold can be obtained from $m$-ball by gluing some points on the boundary. Is it still true for topological manifold? Comments: To proof the smo …
9 votes
1 answer
340 views

Ramified cover of 3-ball

I it true that any connected oriented 3-manifold with nonempty boundary can be obtained as a ramified cover of 3-ball with a ramification at a link? link = a 1-dimensional submanifold with possibly …