Igor Belegradek's user avatar
Igor Belegradek's user avatar
Igor Belegradek's user avatar
Igor Belegradek
  • Member for 14 years, 5 months
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16 votes

the criteria for 3-dim manifolds diffeomorphic to $\mathbb{R}^3$

16 votes
Accepted

Do all spaces doubly covered by $S^{2n}$ have the homeomorphism type of $\mathbb{P}^{2n}_{\mathbb{R}}$?

15 votes

Who computed the third stable homotopy group?

15 votes
Accepted

A question on closed geodesics

15 votes
Accepted

Is every vector bundle over a noncompact finite-dimensional manifold a summand of a trivial bundle?

15 votes
Accepted

Does a compact contractible metric space have a point that is fixed by all isometries?

15 votes

Hopfian and Co-Hopfian groups (examples)

15 votes

Undergraduate differential geometry texts

15 votes

exotic differentiable structures on manifolds in dimensions 5 and 6

14 votes

What are the uses of the homotopy groups of spheres?

14 votes

circle action on sphere

14 votes
Accepted

Does homeomorphism between cones imply homeomorphism between sections

14 votes

Is amateur research in mathematics viable?

14 votes
Accepted

Topological embeddings of real projective space in euclidean space

14 votes
Accepted

Homeomorphism/ homotopy types of non-negatively curved manifolds

13 votes
Accepted

When is a bi-Lipschitz homeomorphism smoothable?

13 votes
Accepted

Does Anosov geodesic flow imply asphericity?

13 votes

Why is the first integral Pontryagin class a homeomorphism invariant?

13 votes

Euclidean tangent cone implies Riemannian manifold

13 votes
Accepted

Are there Ricci-flat riemannian manifolds with generic holonomy?

13 votes

Does $\DeclareMathOperator\Aut{Aut}\Aut(\Aut(\dots\Aut(G)\dots))$ stabilize?

13 votes
Accepted

Topology of function spaces?

13 votes

What are some of the big open problems in 3-manifold theory?

13 votes
Accepted

Manifold whose universal covering is a sphere but which is not a space form?

13 votes
Accepted

Trivial fiber bundle

13 votes
Accepted

Piecewise linear (PL) structures on $\mathbf R^4$

13 votes
Accepted

4-dimensional h-cobordisms

13 votes
Accepted

Spaces over which every vector bundle is a summand of the trivial bundle

12 votes

Submitting a companion paper with detailed proofs ?

12 votes

Connected sum of topological manifolds

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