John Klein

Metro Detroit. Brooklyn expatriate.

I'm an algebraic topologist. I also like espresso.

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Thomason's "open letter" to the mathematical community

ag.algebraic-geometry at.algebraic-topology soft-question algebraic-k-theory paper-request asked Oct 1, 2021 at 13:15

mathoverflow.net

28 votes

On the (derived) dual to the James construction.

at.algebraic-topology homotopy-theory asked Feb 4, 2011 at 20:42

mathoverflow.net

19 votes

Local homology of a space of unitary matrices

reference-request at.algebraic-topology differential-topology smooth-manifolds stratifications asked May 2, 2017 at 22:25

mathoverflow.net

18 votes

Geometric interpretation of the Pontryagin square

at.algebraic-topology smooth-manifolds asked Mar 25, 2011 at 18:41

mathoverflow.net

18 votes

Transversality in the proof of the Blakers-Massey Theorem. Is it necessary?

at.algebraic-topology homotopy-theory asked Jan 30, 2011 at 3:15

mathoverflow.net

16 votes

On the wikipedia entry for Borel-Moore homology

at.algebraic-topology homology asked Jul 29, 2013 at 23:16

mathoverflow.net

16 votes

Whitehead products and Framed Manifolds

at.algebraic-topology homotopy-theory smooth-manifolds whitehead-product asked Mar 18, 2016 at 2:20

mathoverflow.net

16 votes

Multiplicativity of the Euler characteristic for fibrations

reference-request at.algebraic-topology asked Feb 24, 2022 at 16:43

mathoverflow.net

15 votes

"Strøm-type" model structure on chain complexes?

at.algebraic-topology model-categories asked Jan 19, 2011 at 12:34

mathoverflow.net

13 votes

"Burnside ring" of the natural numbers and algebraic K-theory

at.algebraic-topology rt.representation-theory algebraic-k-theory asked Apr 7, 2022 at 20:40

mathoverflow.net

Top Answers

Can anyone explain to me what is an assembly map?

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Groupoid actions on spaces

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A map inducing isomorphisms on homology but not on homotopy

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Fibrations and Cofibrations of spectra are "the same"

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

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What is the intuition behind the Freudenthal suspension theorem?

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Realizing cohomology classes by submanifolds

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Lambda-operations on stable homotopy groups of spheres

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The classifying space of a gauge group

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Finite-dimensionality for de Rham cohomology

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

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

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Choice of base point in a Waldhausen category

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

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Parallelizability of the Milnor's exotic spheres in dimension 7

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Computational complexity of computing homotopy groups of spheres

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Unstable manifolds of a Morse function give a CW complex

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Characteristic classes for block bundles

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

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Reverse map of a homology equivalence.

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do spectra have diagonal maps?

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Uses of Volodin's construction of algebraic K-theory

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Motivation/interpretation for Quillen's Q-construction?

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Why should I prefer bundles to (surjective) submersions?

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"C choose k" where C is topological space

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The space of framed functions

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Definition of Pontrjagin Classes

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Is the J homomorphism compatible with the EHP sequence?

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Does the Borel functor take equivariant fibrations to fibrations?

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Natural transformations as categorical homotopies

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