Skip to main content
10 events
when toggle format what by license comment
Jun 15, 2020 at 7:27 history edited CommunityBot
Commonmark migration
Jul 5, 2018 at 8:43 history edited SashaP CC BY-SA 4.0
added 11 characters in body
Sep 9, 2016 at 13:15 comment added SashaP @PaxKivimae I do not now the answer from the top of my head. Probably it is worth asking a separate question.
Sep 5, 2016 at 13:53 comment added Pax Yes, that is what I meant, I seem to be getting worse at writing Tex. But since $H^{r-i}(W\Omega^i)[1/p]$ has sloops in $[i, i+1[$, there is an isogenous $(H^{r-i}(W\Omega^i )[1/p][-i])[i]$, with slopes in $[0, 1[$, and so is the $H^{r-i}(W\Omega^i )[1/p][-i]$ is a Dieudonne module, and can be written as $D(G_i)$. I was just wondering if the $G_i$ had interpretations, since I think that $G_0$ is just the Artin-Mazur formal group.
Sep 5, 2016 at 9:48 comment added SashaP @PaxKivimae No, I do not claim that $H^{r-i}(W\Omega^i)[1/p]=H^r[1/p]$. There is a direct sum decomposition(exactly as in Hodge theory)$H^r[1/p]=\bigoplus_i H^{r-i}(W\Omega^i)[1/p]$ compatible with Frobenius action and summand $H^{r-i}(W\Omega^i)[1/p]$ has slopes in the interval $[i,i+1[$.
Sep 5, 2016 at 9:44 history edited SashaP CC BY-SA 3.0
added 25 characters in body
Sep 4, 2016 at 23:11 comment added Pax groups obtained from the shift operator and duality, $D^{-1}(C[-i][i])$ as remarked by Groethendieck (I forget where though).
Sep 4, 2016 at 23:09 comment added Pax This answer is exactly what I was looking for! Glad to have an intuitive proof on hand before braving Illusie (especially since my french is horrendous). The equality $H^{r-i}(W\Omega^i)[1/p]=H^r[1/p]$ is very interesting. I believe we have that $H^r(W\Omega^0)=H^r(X, W)=H^r(X, D\mathbb{G}_m)=D(H^r(X, \mathbb{G}_m))$, for the last object being the formal group associated to $Ker(H^r(X\times Spec(A))\to H^r(X))$ (we might need some smoothness conditions here). Are there similar interpretations of the higher $H^{r-i}(W\Omega^i)[1/p]$ in terms of formal groups? I believe these are the formal
Sep 4, 2016 at 22:57 vote accept Pax
Sep 4, 2016 at 22:31 history answered SashaP CC BY-SA 3.0