bio | website | wwwmath.uni-muenster.de/… |
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location | Münster | |
age | 37 | |
visits | member for | 3 years, 6 months |
seen | yesterday | |
stats | profile views | 4,110 |
I am a mathematician based in Münster, Germany. A fellow MO user once described me as a ''very homotopy-theoretic geometric topologist'' and I largely approve this description.
Apr 9 |
awarded | Enlightened |
Apr 9 |
awarded | Nice Answer |
Mar 14 |
comment |
What is the group of pointed homotopy classes of maps from $S^3 \times S^3$ to $S^3$?
Nice answer. I gues you mean $HP^{\infty}$, not $HP^4$. |
Feb 26 |
answered | Integral formula for Euler class |
Feb 13 |
comment |
On a homological finiteness condition
@Fernando, Michal: yes, the problem is the direction of the arrow. But the paper you linked to seems very interesting. |
Feb 13 |
revised |
On a homological finiteness condition
edited tags |
Feb 12 |
revised |
On a homological finiteness condition
added 97 characters in body |
Feb 12 |
awarded | Nice Question |
Feb 12 |
comment |
On a homological finiteness condition
@Igor: I guess you mean that for each finite CW, there is a duality group and a map $BG \to X$ (not $X \to BG$). It is fairly easy to produce, for each finite sequence of finite abelian groups, a finite complex that has the sequence of groups as homology: take a wedge of suitable Moore spaces. So: if what you say is true, then any finite sequence of finitely generated abelian groups is the homology of a duality group. |
Feb 12 |
comment |
On a homological finiteness condition
@Misha: my gut feeling is that I should not try to kill $\pi_1$. If $X$ is aspherical, I cannot have a simply connected $Y$ with the desired properties. ''I can explain why'': it would be welcome if you share your insight -:)) |
Feb 12 |
revised |
On a homological finiteness condition
added 456 characters in body |
Feb 12 |
comment |
On a homological finiteness condition
@Vidit: you can assume that $X$ is a simplicial complex, but I do not think this makes it much easier. |
Feb 12 |
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On a homological finiteness condition
yes: in order to apply Walls theory, one needs a finite domination and in particular finitely presented fundamental group. Moreover, I do seek for a homology isomorphism, not a homotopy equivalence; and I have no control on the groups, so no chance to rule out the finiteness obstruction. I think it is really a different problem. |
Feb 12 |
revised |
On a homological finiteness condition
added 2 characters in body; edited title |
Feb 12 |
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On a homological finiteness condition
This was my first idea, but I did not find anything that is really close to what i am looking for. |
Feb 12 |
asked | On a homological finiteness condition |
Feb 2 |
comment |
Space of embeddings of circle in a surface
There is a result by Gramain (1973, Le type d'homotopie...) which says that the space $Emb((S^1,v),(M,w))$ of embeddings with prescribed behaviour on a fixed unit tangent vector has contractible components, for each compact surface. His proof is purely topological. This should imply what you are looking for, though I do not see it immediately. |
Feb 2 |
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Adams' theorems on the Hopf-Whitehead J-homomorphism
If I want to show that the $J$-homomorphism is injective on $\pi_{8n}$, I have to show that a homotopy $8n+1$-sphere is stably parallelizable, but unfortunately the only argument known to me uses the fact on the $J$-homomorphism. So it seems to be circular. |
Feb 2 |
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Adams' theorems on the Hopf-Whitehead J-homomorphism
Ok, now I understand what you are saying. But I do not see how you turn the disc into a standard disc, i.e. why the ''framing does extend''. |
Feb 2 |
awarded | Nice Question |