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fritz
  • Member for 11 years, 5 months
  • Last seen more than a month ago
7 votes
1 answer
319 views

topological group operation vs homotopy group operation

4 votes
1 answer
297 views

question from hatcher basic 3 manifolds

4 votes
1 answer
140 views

$\pi_2(X)$ defined with closed surfaces instead of spheres

4 votes
1 answer
154 views

Examples of connections between bounded cohomology and geometric properties of groups

3 votes
2 answers
58 views

What are good references for the action of $\Gamma := \pi_1(S)$ on $S^1 = \partial \mathbb{H}^2$, where $S$ is a closed hyperbolic surface

3 votes
0 answers
124 views

Action of groups on graphs

3 votes
2 answers
798 views

convexity and center of mass in riemannian manifolds

2 votes
1 answer
193 views

is there any relationship between the convexity radii of two "near" points in a riemannian manifold?

2 votes
0 answers
176 views

lifting injective maps to injective maps in principal bundles

2 votes
1 answer
255 views

morphisms of principal bundles with different structure groups

2 votes
0 answers
150 views

(locally) "almost convex" property of the distance function in a general Riemannian manifold

2 votes
0 answers
140 views

is a free cellular action of a discrete group over a cellular complex always properly discontinuous?

2 votes
2 answers
541 views

If X is a simplicial complex, are the complex of simplicial chains and the one of cellular chains of X identical?

1 vote
1 answer
118 views

homomorphisms between amenable (discrete) groups

1 vote
0 answers
630 views

chain homotopy equivalence between mapping cone complexes

1 vote
1 answer
559 views

Does a simply connected complete riemannian manifold with POSITIVE upper curvature bound have positive injectivity radius?

1 vote
0 answers
219 views

extending maps from spaces to their whitehead towers

1 vote
0 answers
404 views

"killing homotopy groups" passage

1 vote
0 answers
77 views

Use the Poincaré-Bendixson theorem to construct a Morse function

1 vote
1 answer
361 views

is it possible to derive the künneth theorem from serre spectral sequences?

1 vote
1 answer
55 views

Are there formulas to get the (co)homology of a group $G$ from a presentation of $G$?

0 votes
2 answers
95 views

Can a group G generated by $k$ elements act properly discontinuously freely and cocompactly on $\mathbb{R}^n$, for $n > k$

0 votes
1 answer
145 views

Are there "interesting" examples of complete finite-volume non-compact Riemannian manifolds that are not non-positively curved?