User John Klein

34 votes

Accepted

Can anyone explain to me what is an assembly map?

answered Mar 2, 2012 at 4:38

26 votes

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Groupoid actions on spaces

answered Apr 29, 2011 at 20:23

22 votes

A map inducing isomorphisms on homology but not on homotopy

answered Aug 12, 2012 at 3:38

19 votes

Fibrations and Cofibrations of spectra are "the same"

answered Jul 29, 2014 at 6:15

19 votes

Is any CW complex with only finitely many nonzero homology groups homotopic to a finite dimensional CW complex?

answered Apr 26, 2017 at 23:00

18 votes

Lambda-operations on stable homotopy groups of spheres

answered Nov 8, 2012 at 15:19

18 votes

What is the intuition behind the Freudenthal suspension theorem?

answered Feb 23, 2011 at 23:46

18 votes

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Realizing cohomology classes by submanifolds

answered May 24, 2019 at 17:51

17 votes

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Immersions of surfaces in $\mathbb{R}^3$

answered Jul 9, 2019 at 0:30

17 votes

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Finite-dimensionality for de Rham cohomology

answered Feb 17, 2011 at 0:15

17 votes

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The classifying space of a gauge group

answered May 9, 2013 at 2:02

16 votes

Is an A-infinity thing the same the same as strict thing viewed through a homotopy equivalence?

answered Jan 12, 2011 at 3:00

16 votes

What does actually being a CW-complex provide in algebraic topology?

answered Sep 11, 2011 at 15:03

16 votes

Choice of base point in a Waldhausen category

answered Apr 9, 2012 at 21:11

15 votes

Computational complexity of computing homotopy groups of spheres

answered May 9, 2012 at 1:32

15 votes

Parallelizability of the Milnor's exotic spheres in dimension 7

answered Mar 11, 2011 at 16:59

14 votes

How to prove the connected sum of two closed aspherical n-manfolds (n >2) is not asperical?

answered Jan 13, 2011 at 1:15

14 votes

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Characteristic classes for block bundles

answered May 20, 2012 at 15:09

14 votes

Unstable manifolds of a Morse function give a CW complex

answered Nov 24, 2019 at 16:41

13 votes

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Reverse map of a homology equivalence.

answered Aug 30, 2012 at 15:58

13 votes

do spectra have diagonal maps?

answered Jan 1, 2012 at 16:20

12 votes

Motivation/interpretation for Quillen's Q-construction?

answered Dec 11, 2011 at 5:09

12 votes

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Definition of Pontrjagin Classes

answered Dec 21, 2011 at 18:57

12 votes

The space of framed functions

answered Dec 24, 2010 at 17:34

12 votes

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"C choose k" where C is topological space

answered Dec 30, 2010 at 3:13

12 votes

Why should I prefer bundles to (surjective) submersions?

answered Jan 23, 2011 at 18:57

12 votes

Accepted

Is the J homomorphism compatible with the EHP sequence?

answered Sep 1, 2016 at 16:16

12 votes

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Uses of Volodin's construction of algebraic K-theory

answered Aug 30, 2021 at 23:32

11 votes

Homotopy classification of selfmaps of product of spheres?

answered Dec 31, 2015 at 18:56

11 votes

Accepted

Linking topological spheres

answered Mar 11, 2018 at 20:22

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174 Answers

Can anyone explain to me what is an assembly map?

Groupoid actions on spaces

A map inducing isomorphisms on homology but not on homotopy

Fibrations and Cofibrations of spectra are "the same"

Is any CW complex with only finitely many nonzero homology groups homotopic to a finite dimensional CW complex?

Lambda-operations on stable homotopy groups of spheres

What is the intuition behind the Freudenthal suspension theorem?

Realizing cohomology classes by submanifolds

Immersions of surfaces in $\mathbb{R}^3$

Finite-dimensionality for de Rham cohomology

The classifying space of a gauge group

Is an A-infinity thing the same the same as strict thing viewed through a homotopy equivalence?

What does actually being a CW-complex provide in algebraic topology?

Choice of base point in a Waldhausen category

Computational complexity of computing homotopy groups of spheres

Parallelizability of the Milnor's exotic spheres in dimension 7

How to prove the connected sum of two closed aspherical n-manfolds (n >2) is not asperical?

Characteristic classes for block bundles

Unstable manifolds of a Morse function give a CW complex

Reverse map of a homology equivalence.

do spectra have diagonal maps?

Motivation/interpretation for Quillen's Q-construction?

Definition of Pontrjagin Classes

The space of framed functions

"C choose k" where C is topological space

Why should I prefer bundles to (surjective) submersions?

Is the J homomorphism compatible with the EHP sequence?

Uses of Volodin's construction of algebraic K-theory

Homotopy classification of selfmaps of product of spheres?

Linking topological spheres