Skip to main content
Robert Cardona's user avatar
Robert Cardona's user avatar
Robert Cardona's user avatar
Robert Cardona
  • Member for 11 years, 10 months
  • Last seen more than 4 years ago
comment
Mayer Vietoris Spectral sequence for topological K theory
Yes of course, that question was just for me. Thanks.
comment
Mayer Vietoris Spectral sequence for topological K theory
I added references and a remark on cofibrancy issues. If we require all the finite intersections to be cofibrant, that's enough to recover your argument. Also, what is your intuition for quickly seeing what the Moore normalization is? I never had intuition for this as the definition is somewhat involved, and tend to stick with the alternating face map complex for simplicity. But this is something I'd like to have a feel for: just looking at it and saying: "ahh the normalization is this which is much nicer to look at."
revised
Mayer Vietoris Spectral sequence for topological K theory
Fixed typo's regarding simplicial indices; Added references; fixed typo's in last equation regarding script types.
Loading…
awarded
awarded
revised
Mayer Vietoris Spectral sequence for topological K theory
Added required condition on referenced theorem that does not always hold; proposed path to recover the desired result.
Loading…
comment
Mayer Vietoris Spectral sequence for topological K theory
Possibly. Each term in the first page should be able to be described as the homology of the simplicial replacement of this simplicial space composed with the cohomology functors, which in some sense contains these tuplewise intersections; but it doesn't look as nice as this description. It contains too much information, and it is not obvious (except for maybe the two cover) that on passing to the second page that extra information gets wiped out and your left with the nicer description above.
comment
Mayer Vietoris Spectral sequence for topological K theory
Here's an alternate approach: given a spectrum, we can construct the homotopy colimit spectral sequence associated to a diagram, which in this case we choose to be this simplicial space you defined above. Since the homotopy colimit of that simplicial space is weakly equivalent to $X$, we get the convergence to the homology of the space $X$. The second page can then be described in terms of the derived colimit functors, and the spectrum. Definitely not as concise a description as yours, at the second page. Actually, this is exactly @DenisNardin s answer. I may edit this wiki later.
comment
Mayer Vietoris Spectral sequence for topological K theory
The theorem you reference presupposes the simplicial space is Reedy cofibrant, which I don't think this simplicial space you define is, generally. You might be able to recover something with a cofibrant replacement functor. Also, Dugger shows that the geometric realization of this simplicial space is always weakly equivalent to $X$, which should give the desired isomorphism.
awarded
awarded
awarded