User Peter May

21 votes

Is there the Whitehead theorem for cohomology theory?

answered Mar 12, 2011 at 4:51

21 votes

Accepted

Equivariant homotopy theory: some history questions

answered Sep 4, 2012 at 1:07

20 votes

Accepted

Is the $\infty$-category of spectra “convenient”?

answered Feb 9, 2019 at 3:00

20 votes

Accepted

Structure of Hopf algebras - trouble understanding an old paper

answered Sep 18, 2015 at 4:04

20 votes

Compelling evidence that two basepoints are better than one

answered Apr 21, 2013 at 18:52

20 votes

Accepted

A category with weak equivalences that is not a model category

answered Jun 7, 2013 at 12:50

19 votes

Accepted

Homotopy extension of $E_{\infty}$-spaces

answered Jan 4, 2020 at 15:33

19 votes

"A gentleman never chooses a basis."

answered Sep 17, 2012 at 18:36

19 votes

Accepted

Computing homotopies

answered Feb 4, 2011 at 2:47

19 votes

A question about the topological proofs of Bott periodicity

answered Jan 2, 2012 at 1:46

18 votes

Intuition/idea behind a proof of the splitting principle?

answered Feb 5, 2016 at 4:26

18 votes

Accepted

How much of homotopy theory can be done using only finite topological spaces?

answered Jul 31, 2014 at 2:17

17 votes

Accepted

Proving that a space cannot be delooped.

answered Apr 13, 2013 at 1:01

17 votes

nontrivial isomorphisms of categories

answered Jun 28, 2012 at 17:49

17 votes

Why are equivariant homotopy groups not RO(G)-graded?

answered Nov 11, 2011 at 3:38

17 votes

Accepted

What is the functor tensor product?

answered Jul 27, 2012 at 2:46

17 votes

What is a simplicial commutative ring from the point of view of homotopy theory?

answered Jan 11, 2013 at 21:26

17 votes

Accepted

Do people still use Massey Products for computations in the Adams Spectral Sequence

answered Nov 16, 2012 at 17:54

16 votes

Accepted

Some calculations with the Adams spectral sequence and the cobar complex

answered May 23, 2012 at 15:14

15 votes

Accepted

Weak Bott periodicity vs. strong Bott periodicity

answered Mar 26, 2012 at 14:02

15 votes

Segal's Original Definition of a Topological Category

answered Jan 15, 2012 at 16:13

15 votes

Algebras over the little disks operad

answered Mar 21, 2012 at 16:57

15 votes

How canonical is cofibrant replacement?

answered Feb 6, 2011 at 22:55

15 votes

Accepted

Classifying spaces of E_1 - spaces

answered Mar 15, 2011 at 20:12

15 votes

What are some interesting problems in the intersection of Algebraic Number Theory and Algebraic Topology?

answered Jul 27, 2012 at 2:18

15 votes

Künneth formula for cohomology

answered Sep 21, 2012 at 18:09

15 votes

Accepted

Computing multiplication in the Ext (for a simple example)

answered Aug 12, 2013 at 17:50

15 votes

Is there a (satisfying) proof that cellular cohomology is isomorphic to simplicial cohomology that doesn't use relative cohomlogy?

answered May 14, 2015 at 1:27

15 votes

Accepted

Naturality of Moore-Postnikov systems

answered Mar 7, 2018 at 4:26

15 votes

Analogy between Stiefel-Whitney and Chern classes

answered May 11, 2020 at 4:14

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268 Answers

Is there the Whitehead theorem for cohomology theory?

Equivariant homotopy theory: some history questions

Is the $\infty$-category of spectra “convenient”?

Structure of Hopf algebras - trouble understanding an old paper

Compelling evidence that two basepoints are better than one

A category with weak equivalences that is not a model category

Homotopy extension of $E_{\infty}$-spaces

"A gentleman never chooses a basis."

Computing homotopies

A question about the topological proofs of Bott periodicity

Intuition/idea behind a proof of the splitting principle?

How much of homotopy theory can be done using only finite topological spaces?

Proving that a space cannot be delooped.

nontrivial isomorphisms of categories

Why are equivariant homotopy groups not RO(G)-graded?

What is the functor tensor product?

What is a simplicial commutative ring from the point of view of homotopy theory?

Do people still use Massey Products for computations in the Adams Spectral Sequence

Some calculations with the Adams spectral sequence and the cobar complex

Weak Bott periodicity vs. strong Bott periodicity

Segal's Original Definition of a Topological Category

Algebras over the little disks operad

How canonical is cofibrant replacement?

Classifying spaces of E_1 - spaces

What are some interesting problems in the intersection of Algebraic Number Theory and Algebraic Topology?

Künneth formula for cohomology

Computing multiplication in the Ext (for a simple example)

Is there a (satisfying) proof that cellular cohomology is isomorphic to simplicial cohomology that doesn't use relative cohomlogy?

Naturality of Moore-Postnikov systems

Analogy between Stiefel-Whitney and Chern classes