User Jeff Strom

37 votes

2 answers

2k views

Finite complexes whose homotopy groups are not "finitely generated"

asked May 29, 2014 at 1:32

25 votes

1 answer

2k views

Bouncing a ball down the stairs

recreational-mathematics classical-mechanics statistical-physics

asked Jun 19, 2014 at 0:59

19 votes

4 answers

2k views

Difference between represented and singular cohomology?

at.algebraic-topology homotopy-theory cohomology

asked Jun 24, 2010 at 20:28

17 votes

1 answer

1k views

Slick Proof of Kudo Transgression Theorem

at.algebraic-topology homotopy-theory spectral-sequences

asked Mar 11, 2011 at 1:27

15 votes

2 answers

877 views

Pointed Hurewicz model structure

homotopy-theory model-categories at.algebraic-topology

asked Nov 30, 2010 at 4:29

14 votes

5 answers

2k views

Good reference for homology of $K(\mathbb{Z}, 2n)$?

at.algebraic-topology homotopy-theory

asked Jun 7, 2010 at 16:56

13 votes

2 answers

3k views

Left and right eigenvalues

lie-groups linear-algebra ag.algebraic-geometry matrices noncommutative-algebra

asked Jul 17, 2010 at 17:13

12 votes

0 answers

615 views

Mapping cylinders of fibrations

at.algebraic-topology homotopy-theory

asked Dec 15, 2010 at 14:46

12 votes

1 answer

589 views

Open subspaces of CW complexes

at.algebraic-topology gn.general-topology homotopy-theory

asked Aug 26, 2019 at 15:11

11 votes

2 answers

2k views

Quasifibrations and homotopy pullbacks

homotopy-theory at.algebraic-topology

asked Jan 30, 2011 at 14:23

11 votes

2 answers

578 views

Spaces that invert weak homotopy equivalences.

at.algebraic-topology homotopy-theory

asked Nov 23, 2010 at 2:15

10 votes

2 answers

677 views

Model categories of simplicial objects

homotopy-theory at.algebraic-topology model-categories simplicial-stuff

asked Jan 12, 2011 at 18:46

9 votes

1 answer

254 views

Retracting a wedge of spheres off a homotopy fiber

at.algebraic-topology homotopy-theory

asked Feb 10, 2018 at 17:12

9 votes

0 answers

254 views

When is an increasing union a colimit?

reference-request at.algebraic-topology homotopy-theory model-categories limits-and-colimits

asked Jul 29, 2020 at 15:53

8 votes

1 answer

193 views

Pointed versus unpointed maps into a topological monoid

at.algebraic-topology homotopy-theory topological-groups topological-semigroups-and-monoids

asked Mar 12, 2021 at 14:15

8 votes

1 answer

205 views

Splitting low-dimensional $p$-local CW complexes for large $p$

at.algebraic-topology homotopy-theory

asked Jun 14, 2019 at 14:38

8 votes

3 answers

491 views

Order of the identity map of a Moore space.

homotopy-theory at.algebraic-topology reference-request

asked Nov 19, 2010 at 3:01

8 votes

1 answer

998 views

Are there homotopy equivalences that are not weak homotopy equivalences?

homotopy-theory at.algebraic-topology

asked Jul 15, 2010 at 19:22

8 votes

2 answers

2k views

Splitting of the Universal Coefficients sequence

at.algebraic-topology homotopy-theory homological-algebra cohomology

asked Jun 13, 2010 at 1:26

7 votes

1 answer

190 views

Injectivity of Rewrite Rule in a Free Lie Algebra

lie-algebras

asked Nov 21, 2014 at 20:45

7 votes

1 answer

370 views

Pushouts and products in categories

reference-request ct.category-theory

asked Sep 11, 2020 at 14:35

7 votes

0 answers

82 views

Stable splitting of products

homotopy-theory

asked Aug 1, 2019 at 13:29

7 votes

1 answer

192 views

Quasifibrations and transfinite filtrations

at.algebraic-topology gn.general-topology homotopy-theory

asked May 21, 2021 at 21:16

6 votes

2 answers

172 views

Nonhomeomophic spaces with homeomorphic mapping cones

at.algebraic-topology gn.general-topology

asked Aug 26, 2020 at 0:22

6 votes

1 answer

1k views

Solid rings and Tor

ra.rings-and-algebras tensor-products homological-algebra at.algebraic-topology

asked Apr 25, 2012 at 13:57

6 votes

0 answers

272 views

Reference request: splittings in rational homotopy theory

homotopy-theory at.algebraic-topology rational-homotopy-theory

asked May 4, 2012 at 2:00

6 votes

0 answers

76 views

Examples of maps with nontrivial Hopf invariant but Lusternik-Schnirelmann category of the cofiber doesn't increase?

at.algebraic-topology homotopy-theory

asked Jun 24, 2016 at 13:47

6 votes

0 answers

461 views

The Mapping Cylinder of a Pullback Square

at.algebraic-topology homotopy-theory gn.general-topology

asked Sep 22, 2010 at 14:48

6 votes

1 answer

548 views

Origin of "versal"?

terminology ct.category-theory

asked Nov 24, 2010 at 15:54

6 votes

0 answers

347 views

The Space of Cellular Maps

at.algebraic-topology homotopy-theory gn.general-topology cw-complexes mapping-space

asked Nov 10, 2010 at 18:44

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66 Questions

Finite complexes whose homotopy groups are not "finitely generated"

Bouncing a ball down the stairs

Difference between represented and singular cohomology?

Slick Proof of Kudo Transgression Theorem

Pointed Hurewicz model structure

Good reference for homology of $K(\mathbb{Z}, 2n)$?

Left and right eigenvalues

Mapping cylinders of fibrations

Open subspaces of CW complexes

Quasifibrations and homotopy pullbacks

Spaces that invert weak homotopy equivalences.

Model categories of simplicial objects

Retracting a wedge of spheres off a homotopy fiber

When is an increasing union a colimit?

Pointed versus unpointed maps into a topological monoid

Splitting low-dimensional $p$-local CW complexes for large $p$

Order of the identity map of a Moore space.

Are there homotopy equivalences that are not weak homotopy equivalences?

Splitting of the Universal Coefficients sequence

Injectivity of Rewrite Rule in a Free Lie Algebra

Pushouts and products in categories

Stable splitting of products

Quasifibrations and transfinite filtrations

Nonhomeomophic spaces with homeomorphic mapping cones

Solid rings and Tor

Reference request: splittings in rational homotopy theory

Examples of maps with nontrivial Hopf invariant but Lusternik-Schnirelmann category of the cofiber doesn't increase?

The Mapping Cylinder of a Pullback Square

Origin of "versal"?

The Space of Cellular Maps