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John Klein's user avatar
John Klein's user avatar
John Klein's user avatar
John Klein
  • Member for 14 years, 4 months
  • Last seen this week
  • Metro Detroit. Brooklyn expatriate.
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I'm an algebraic topologist. I also like espresso.

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Top posts
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question
63
Thomason's "open letter" to the mathematical community
Oct 1, 2021
answer
35
Can anyone explain to me what is an assembly map?
Mar 2, 2012
question
28
On the (derived) dual to the James construction.
Feb 4, 2011
answer
27
Groupoid actions on spaces
Apr 29, 2011
answer
23
A map inducing isomorphisms on homology but not on homotopy
Aug 12, 2012
answer
20
Lambda-operations on stable homotopy groups of spheres
Nov 8, 2012
answer
19
Realizing cohomology classes by submanifolds
May 24, 2019
answer
19
Is any CW complex with only finitely many nonzero homology groups homotopic to a finite dimensional CW complex?
Apr 26, 2017
answer
19
Fibrations and Cofibrations of spectra are "the same"
Jul 29, 2014
question
18
Geometric interpretation of the Pontryagin square
Mar 25, 2011