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209
Answers
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47
Example of an unnatural isomorphism
Aug 14 '13 at 8:04
37
Suggestions for good notation
Oct 20 '10 at 20:52
27
Can one deform an immersion of a 3-manifold in $\mathbb R^4$ to an embedding in $\mathbb R^6$?
Dec 14 '15 at 20:48
23
A possible generalization of the homotopy groups.
Sep 7 '10 at 9:03
21
Restriction of “$\pi_{1}$” to topological groups
Feb 24 '14 at 15:43
20
H-space structures on non-sphere suspensions?
Apr 10 at 19:45
20
In knot theory: Benefits of working in $S^3$ instead of $\mathbb{R}^3$?
Apr 27 '11 at 13:24
17
How should one think about pushforward in cohomology?
May 12 '11 at 7:11
17
Which of Quillen's Papers Should I read?
May 6 '11 at 5:56
16
rational homotopy of a manifold
Dec 9 '12 at 20:55
16
Null-homotopy of diagonal map
Feb 22 '11 at 8:24
15
Does every dimension $n\geq4$ admit a manifold with an exotic smooth structure?
May 18 at 9:00
14
Unstable homotopy groups of spheres beyond Toda's range
Dec 18 '14 at 20:19
14
What is the 31th homotopy group of the 2 - sphere ?
May 17 '13 at 9:04
14
Homology of infinite loop spaces $QX$
Jan 26 '12 at 14:25
14
Is every homology theory given by a spectrum?
May 5 '11 at 7:03
13
Classification of $O(2)$-bundles in terms of characteristic classes
Mar 26 at 10:01
13
homology classes as immersed submanifolds
Mar 3 '11 at 7:24
13
Divisibility of a binomial coefficient by $p^2$ — current status
Nov 13 '10 at 15:19
11
Cohomology ring of a fiberwise join
Apr 30 at 15:24
11
What is the 'non-intuitive' part in sphere eversion (turning inside out)?
Aug 29 '12 at 12:56
11
(Co)homology of the Eilenberg-MacLane spaces K(G.n)
Aug 16 '11 at 9:00
10
The cohomology plus what characterizes the rational homotopy type?
Mar 30 '14 at 16:31
10
Integral versus real (universal) characteristic classes
Dec 17 '13 at 7:34
10
Can group cohomology be interpreted as an obstruction to lifts?
May 16 '13 at 6:27
10
Is the singular homology of a real algebraic set always finitely generated?
May 28 '12 at 12:58
10
Geometric Interpretation of the Lower Central Series for the Fundamental Group?
Jan 31 '12 at 22:54
10
cohomology of BG, G compact Lie group
Apr 15 '11 at 7:47
10
Which Groups are Infinite Loop Spaces?
Oct 20 '10 at 7:22
9
Steenrod operations on cohomology of grassmannians
Sep 2 '15 at 12:55
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