User Matthias Wendt

37 votes

Accepted

$H^4(BG,\mathbb Z)$ torsion free for $G$ a connected Lie group

answered Oct 1, 2014 at 18:09

35 votes

What is the status of the Friedlander-Milnor conjecture today?

answered May 15, 2014 at 9:33

27 votes

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Hilbert's 3rd problem,number theory, motives, cyclic homology,...

answered Oct 31, 2015 at 19:13

27 votes

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Steenrod operations in etale cohomology?

answered Mar 17, 2016 at 9:07

24 votes

The first unstable homotopy group of $Sp(n)$

answered Mar 24, 2018 at 19:41

21 votes

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What was a "cusp" to Hurwitz in 1892?

answered Mar 10, 2016 at 10:18

21 votes

Unusual symmetries of the Cayley-Menger determinant for the volume of tetrahedra

answered Jan 16, 2017 at 19:57

20 votes

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Two definitions of Lebesgue covering dimension

answered Jan 17, 2016 at 14:31

19 votes

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(really) basic intuition for $\mathbb A^1$-homotopy theory

answered Jan 13, 2016 at 11:34

19 votes

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Symplectic K-theory

answered Feb 17, 2015 at 14:33

18 votes

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Stable homotopy groups of $RP^{\infty}$

answered Feb 10, 2016 at 19:42

17 votes

Accepted

Besides $F_q$, for which rings $R$ is $K_i(R)$ completely known?

answered Aug 20, 2014 at 12:41

15 votes

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Over which fields (of positive characteristic) is the Beilinson-Soulé vanishing conjecture known to hold?

answered May 16, 2014 at 13:36

14 votes

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Borel-Serre compactification of $\mathbb{H}^3 / SL_2(\mathcal{O}_K)$

answered Jul 23, 2014 at 20:12

14 votes

Accepted

What is the fundamental group of $\mathcal O_{\mathbb P^n}(k)$ minus the zero section

answered Sep 28, 2017 at 13:41

14 votes

Integral cohomology of $SU(n)$ - looking for constants

answered Jun 15, 2017 at 9:05

14 votes

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Fourth obstruction, Pontryagin and Euler class

answered Aug 9, 2018 at 15:46

13 votes

Accepted

Computation of $\pi_4$ of simple Lie groups

answered Jan 13, 2017 at 17:22

13 votes

Accepted

Which motivic cohomology groups of complex numbers are non-torsion?

answered Aug 23, 2017 at 14:44

12 votes

Is a topological fiber-bundle, whose total space admits a retraction onto a fiber, trivial?

answered Sep 22, 2017 at 19:13

12 votes

Yoga of six functors for group representations?

answered Jan 24, 2017 at 19:50

12 votes

Intuition for Zagier's theorem for $\zeta_K(2)$

answered Nov 15, 2015 at 20:05

12 votes

Motivation for equivariant homotopy theory?

answered Nov 2, 2015 at 11:02

12 votes

why Borel's computation implies Beilinson-Soulé?

answered Jun 18, 2014 at 10:22

12 votes

Quillen + construction for finite groups

answered Oct 9, 2017 at 11:45

11 votes

Accepted

Chow ring of Hilbert scheme of 4 points in $\mathbb{P}^2$

answered Jan 5, 2018 at 19:06

11 votes

rational cohomology of finite real grassmannian

answered Sep 27, 2017 at 11:12

11 votes

Accepted

What is the coefficient ring of algebraic K theory of the discrete $\mathbb{C}$?

answered May 15, 2014 at 17:21

11 votes

What is obstructing two stably-isomorphic vector bundles from being isomorphic?

answered Feb 15, 2015 at 15:40

11 votes

Accepted

classifying space and cohomology of integer general linear group

answered Feb 5, 2015 at 9:18

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194 Answers

$H^4(BG,\mathbb Z)$ torsion free for $G$ a connected Lie group

What is the status of the Friedlander-Milnor conjecture today?

Hilbert's 3rd problem,number theory, motives, cyclic homology,...

Steenrod operations in etale cohomology?

The first unstable homotopy group of $Sp(n)$

What was a "cusp" to Hurwitz in 1892?

Unusual symmetries of the Cayley-Menger determinant for the volume of tetrahedra

Two definitions of Lebesgue covering dimension

(really) basic intuition for $\mathbb A^1$-homotopy theory

Symplectic K-theory

Stable homotopy groups of $RP^{\infty}$

Besides $F_q$, for which rings $R$ is $K_i(R)$ completely known?

Over which fields (of positive characteristic) is the Beilinson-Soulé vanishing conjecture known to hold?

Borel-Serre compactification of $\mathbb{H}^3 / SL_2(\mathcal{O}_K)$

What is the fundamental group of $\mathcal O_{\mathbb P^n}(k)$ minus the zero section

Integral cohomology of $SU(n)$ - looking for constants

Fourth obstruction, Pontryagin and Euler class

Computation of $\pi_4$ of simple Lie groups

Which motivic cohomology groups of complex numbers are non-torsion?

Is a topological fiber-bundle, whose total space admits a retraction onto a fiber, trivial?

Yoga of six functors for group representations?

Intuition for Zagier's theorem for $\zeta_K(2)$

Motivation for equivariant homotopy theory?

why Borel's computation implies Beilinson-Soulé?

Quillen + construction for finite groups

Chow ring of Hilbert scheme of 4 points in $\mathbb{P}^2$

rational cohomology of finite real grassmannian

What is the coefficient ring of algebraic K theory of the discrete $\mathbb{C}$?

What is obstructing two stably-isomorphic vector bundles from being isomorphic?

classifying space and cohomology of integer general linear group