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Achim Krause's user avatar
Achim Krause's user avatar
Achim Krause's user avatar
Achim Krause
  • Member for 11 years, 3 months
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113 Answers

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10 votes
Accepted

The number of polynomials on a finite group, II

10 votes
Accepted

($1$-)pullbacks of Kan complexes

9 votes

Is the cohomology ring $H^*(BG,\mathbb{Z})$ generated by Euler classes?

9 votes

Is there a definition of reduced $E_\infty$ ring?

9 votes
Accepted

Abstract simplicial complexes - Reference for an elementary definition of mapping degree for simplicial maps?

9 votes
Accepted

Galois action on algebraic K-theory of finite fields

9 votes

Tensor product over $\mathbb{Z}$ and p-adic integer ring $\mathbb{Z}_p$

8 votes
Accepted

The action of $\operatorname{Gal}(\overline{k}/k)$ on $\pi_1^{\mathrm{ét}}(\mathbb{G}_m)$

8 votes
Accepted

Algebraic independence of polynomials when truncated imply algebraic independence of the entire polynomial?

8 votes

Retract of a product

8 votes
Accepted

Why is $bo$ not flat?

8 votes

Does a non-singular matrix have a large minor with disjoint rows and columns and full rank?

8 votes
Accepted

Is there a Hopf algebra-style description of chain complexes?

8 votes
Accepted

Where does this clever choice of differential come from? (calculating $\mathrm{H}^1_{\mathrm{dR}}(E/k))$

8 votes

Embedding an icosahedron

7 votes

Higher homotopy groups of irreducible 3-manifolds

7 votes
Accepted

$(B\mathbb Z/p^{\infty})^{\wedge}_p\rightarrow (BS^1)^{\wedge}_p$ induced by inclusion is an equivalence

7 votes

Given $f: X \to Y$, $g: X \to Z$, when does it exists $h: Y \to Z$ such that $hf \simeq g$?

7 votes

The center of $\mathbf{hTop}$

7 votes

Applications of the Dold-Kan correspondence

7 votes

A very elementary question on the definition of sheaf on a site

7 votes
Accepted

Definition of the Yoneda Ext

7 votes

Formula for compositions of Steenrod squares that produce a form in the top degree

7 votes
Accepted

Infinite suspension is cotangent complex

7 votes
Accepted

Reference for homotopy groups of filtered homotopy colimits

7 votes
Accepted

Does the homotopy category of finite spectra act on stable homotopy categories?

7 votes
Accepted

Pontryagin dual of a group-cohomology class

7 votes

K-theory of simplicial rings

7 votes
Accepted

Double hom with $\mathbb{CP}^\infty$

7 votes
Accepted

Is there a $ H_* H^* $-theory which is naturally a common generalization both of singular homology and de Rham (or singular) cohomology?