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Dec 27, 2014 at 14:55 comment added Tyler Lawson @SeanTilson $THH$ preserves localization: $S^{-1} THH(R) = THH(S^{-1} R)$. As a result, by taking an appropriate (homotopy) limit over a Čech nerve you can patch together the values of $THH$ on open subsets; the fact about localization implies that it's independent of the choice of cover (up to equivalence).
Dec 27, 2014 at 10:55 history edited Max CC BY-SA 3.0
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Dec 26, 2014 at 23:27 comment added Sean Tilson How do we build $THH$ of a smooth projective variety? I would think that one would glue together $THH$ of some of the affine covers, but I am not sure exactly how I would do that in the "right" way. For some reason, I am unclear on how excisive THH is for genuinely commutative ring spectra.
Dec 25, 2014 at 14:27 comment added Fernando Muro Qiaochu of course, did you maybe understand anything different from my comments?
Dec 25, 2014 at 13:22 vote accept Max
Dec 25, 2014 at 11:34 comment added Qiaochu Yuan @Fernando: I think that people want THH to be a genuinely $S^1$-equivariant spectrum, which in particular means that it is more than a spectrum equipped with an action of $S^1$ up to homotopy, and in particular it is equipped with genuine (not homotopy) fixed point data. At least Tyler Lawson's answer below seems to only make sense under that assumption.
Dec 24, 2014 at 15:42 answer added Tyler Lawson timeline score: 5
Dec 24, 2014 at 13:08 comment added Fernando Muro what I mean is that the homotopy fixed points functor is the total left derived functor of the plain fixed points functor, hence if you apply both functors to a cofibrant object you obtain weakly equivalent results, whereas you don't if you apply them to a non-cofibrant object. This is not much, really, and won't be very helpful, so I include it as a comment.
Dec 23, 2014 at 21:57 comment added Max could you say more ?
Dec 23, 2014 at 21:55 comment added Fernando Muro For 1), the answer depends on the explicit model of $THH(X)$ you take.
Dec 23, 2014 at 21:50 history asked Max CC BY-SA 3.0