Roberto Frigerio

Pisa, Italy

http://www.dm.unipi.it/~frigerio/

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Homotopy groups of $S^2$

reference-request at.algebraic-topology homotopy-theory asked May 6, 2011 at 15:34

mathoverflow.net

22 votes

Geodesics on the sphere

dg.differential-geometry mg.metric-geometry ho.history-overview elementary-proofs asked Jan 14, 2019 at 12:55

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18 votes

The number of cusps of higher-dimensional hyperbolic manifolds

hyperbolic-geometry gt.geometric-topology asked Sep 7, 2010 at 15:06

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15 votes

smooth sections of smooth fiber bundles

fibre-bundles at.algebraic-topology smooth-manifolds asked May 25, 2010 at 12:15

mathoverflow.net

13 votes

Fox differential calculus and the Alexander invariant of a link

knot-theory gr.group-theory asked Nov 13, 2011 at 20:22

mathoverflow.net

11 votes

Quasi-isometric rigidity of Nil

gt.geometric-topology lie-groups geometric-group-theory 3-manifolds nilpotent-groups asked Jan 18, 2016 at 11:37

mathoverflow.net

10 votes

Alexandrov angles in Riemannian manifolds

riemannian-geometry mg.metric-geometry soft-question asked Apr 26, 2013 at 22:09

mathoverflow.net

10 votes

Two questions about sphere bundles

at.algebraic-topology fibre-bundles asked Feb 19, 2014 at 17:16

mathoverflow.net

7 votes

Smooth functions on subsets of $\mathbb{R}^n$

differential-topology asked Sep 27, 2018 at 13:59

mathoverflow.net

7 votes

Examples of "exotic" induction

soft-question induction asked Jan 21, 2013 at 17:24

mathoverflow.net

Top Answers

How many elements does it take to normally generate a group?

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Non-commutator in simple group?

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Which knots are singularities of a hyperbolic cone-manifold structures on $S^3$?

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Connections between ultrafilters in topology and logic

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Is there any relationship between measure theory and homology?

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Do you know how to construct a compact hyperbolic 3-manifold with three or four totally geodesic boundary components?

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When does Cantor-Bernstein hold?

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Can anyone give me a good example of two interestingly different ordinary cohomology theories?

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Isometries between metric spaces

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The number of cusps of higher-dimensional hyperbolic manifolds

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Example of a manifold which is not a homogeneous space of any Lie group

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Is there a finitely additive measure on R which is not sigma-additive?

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Is there a combinatorial analogue of Ricci flow?

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Is the cut locus of a generic point in a hyperbolic manifold a generic polyhedron?

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center of fundamental group of finite volume-hyperbolic orbifold

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A name for a weak topology

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Uniquely geodesic and CAT(0) spaces?

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When does a homomorphism factor through a free group?

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