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Oct
13
comment Iterating the suspension-loop adjunction in two different ways
If any reader feels like the bonus paragraph deserves to be asked as a separate question because there are many interesting things to be said with respect to that, tell me and I will.
Oct
13
asked Iterating the suspension-loop adjunction in two different ways
Oct
7
comment Spanish translation for the term operad?
I haven't used it much in Spanish conversations, but I'd say "óperad" is more common.
Sep
29
comment Representations of a cyclic group of order p over a field of characteristic p?
Chapter 6 of these notes is very relevant, and elaborates on Mariano's answer.
Sep
29
comment Cartesian product of two CW-complexes
A caveat: note that what wckronholm calls "attaching maps" is not what Hatcher calls like that: in Hatcher's nomenclature, these would be the "characteristic maps". Note indeed that the product of disks is a disk, but the product of spheres is not a sphere.
Sep
25
accepted Spectral sequence for computing the homotopy fixed points in unstable equivariant homotopy theory
Sep
25
asked The Pontrjagin product for homology at the chain level
Sep
15
awarded  Notable Question
Sep
11
awarded  Nice Answer
Aug
28
awarded  Popular Question
Aug
13
comment Equivalence of Definitions of Principal $G$-bundle
There is another one: a principal $G$-bundle is a fiber bundle with fiber $G$ and structure group $G$ where $G$ acts on itself by left translations. This is the definition of Davis & Kirk.
Jul
18
awarded  Popular Question
Jun
23
comment Any compact embedded $2$-dimensional hypersurface in $\mathbb R^3$ has a point of positive Gaussian curvature
@Dtseng: true, thank you. I've corrected it. Some months after I wrote this answer I wrote it up in all formality here (in Spanish).
Jun
23
revised Any compact embedded $2$-dimensional hypersurface in $\mathbb R^3$ has a point of positive Gaussian curvature
added 36 characters in body
Jun
13
awarded  Revival
Jun
7
comment Homology of a co-h-space manifold
Corollary 13.66 in Switzer's book proves that for any cohomology theory with products, the product is trivial on a suspension. Maybe you can generalize his proof to co-h-spaces.
Jun
3
comment Characterizations of the $p$-Prüfer group
More than four years later, I should edit that seventh item to change those inclusions to "multiply by $p$" maps, but I don't want to bump the question to the front page.
Jun
3
comment Clarify: “$S^0$, $S^1$ and $S^3$ are the only spheres which are also groups”
The point is that the operation gotten from such a set-theoretical bijection has no reason to respect the topological/differentiable structure of $S^k$ in any way. So what they mean is, a group structure in $S^k$ that behaves well with respect to the topology/geometry. (Hence the Lie groups appearing in the answer below).
Jun
2
awarded  Revival
May
29
comment Why is the cartesian product so categorically robust?
This reminds me of this answer: math.stackexchange.com/a/25460/2614