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6 votes
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467 views

Torsionfree crystalline cohomology implies torsionfree etale cohomology?

Let $X$ be a smooth projective variety over an algebraically closed field $k$ of characteristic $p>0$. Let $W=W(k)$ be the ring of Witt vectors of $k$. Assume that the crystalline cohomology $H^2_{...
Monsie's user avatar
  • 91
4 votes
0 answers
262 views

de Rham Bloch-Ogus theory in positive characteristic

In their famous paper Gersten's conjecture and the homology of schemes, one of the results that Bloch and Ogus prove is that the second page of the coniveau spectral sequence for $X$ smooth over a ...
xir's user avatar
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3 votes
0 answers
127 views

Isogeny of elliptic curve over positive characteristic $p$ which does not come from characteristic $0$

Let $K$ be quadratic imaginary field. Let $E$ be an elliptic curve which has CM over $R_K$ ($R_K$ is ring of integers of $K$). According to SIlverman's ''ADvanced topics in the arithmetic of elliptic ...
Duality's user avatar
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3 votes
0 answers
308 views

Invertible Hasse-Witt for non-ordinary curves

Assume that $S$ is a smooth curve of over a field $k$ of characteristic $p>0$ and $f\colon X\to S$ is a relative curve over $S$ (i.e., the fibers are curves). It is well-known that when all the ...
Cyrus's user avatar
  • 395
2 votes
0 answers
279 views

deRham cohomoloy of CM liftings of Jacobians

Let $k$ be field of characteristic $p>0$ and $W=W(k)$ the ring of Witt vectors of $k$. We call a smooth curve over $k$, ordinary, when the Jacobian of $J(X)$ of $X$ is an ordinary abelian variety. ...
Jack's user avatar
  • 637
1 vote
0 answers
120 views

Vanishing theorems that work in positive characteristic

Let $X$ be a smooth projective variety over a field of characteristic $p>0$ of dimension at least $2$. I am looking for some examples when $H^2(\mathcal{O}_X)$ vanishes. Is there any standard way ...
user43198's user avatar
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