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K.J. Moi's user avatar
K.J. Moi's user avatar
K.J. Moi's user avatar
K.J. Moi
  • Member for 15 years, 1 month
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Fundamental group of a topological pullback
That sequence is quite useful, for some reason it usually doesn't appear in algebraic topology books.
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The role of ANR in modern topology
I have also wondered why (algebraic) topologists talk so little about ANRs. I am a homotopy theorist and I learned about them from the $C^{\ast}$-algebraists in my department. Maybe it's because any ANR has the homotopy type of a countable CW-complex.
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K theory of a simplicial monoidal category, Cofinality theorem
Have a look at Staffeldt's "Fundamental theorems of algebraic K-theory", a google search will find it. The problem for you would be that it uses Waldhausen categories and not symmetric monoidal categories but I hope it's heldpful anyway.
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Algebraic K-theory with commutative semirings?
People have certainly been interested in the categorified version of your question (jtopol.oxfordjournals.org/content/4/3/…). Do you have some more context for your question? Is there a particular category of modules or something that you want to understand?
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Geometric meaning of gamma sets
@Kevin: I'm following the conventions I could find in the literature (papers of Segal, Lydakis and Schwede). Anyway, what I want is (covariant) functors from a skeletal subcatory of finite pointed sets. @some guy: I didn't think of that, I'll look into it.
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Nerves of simplicial objects in categories/Waldhausen's S-construction
In the Quillen model structure on simplicial sets it does. I don't know what happens with the Joyal model structure. Next time it might be a good idea to specify which model structure you want for your simplicial sets if you don't want the standard one.
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Nerves of simplicial objects in categories/Waldhausen's S-construction
If we consider a bisimplicial set as a simplicial object in simplicial sets then a levelwise weak equivalence induces a weak equivalence on diagonals, right? Sorry if I'm missing the point here.
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Nerves of simplicial objects in categories/Waldhausen's S-construction
What about taking the nerve in each simplicial degree and then taking the diagonal of the resulting bisimplicial set?
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Functor category
How much of homological algebra can you do in this setting? It seems to me that most homological arguments require the axiom of choice (to lift elements along epis). Do you run into problems when working with these enormous groups?
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