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John Binder
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Assume I have an abelian variety $A$ over a finite field $k$ of characteristic $p$. Work of Norman and Oort (1980) says I can lift $A$ to an abelian variety $\mathscr{A}$ over some characteristic zero ring $R$ with a surjective morphism $R \to k$.

In fact, we can lift $A$ to the Witt ring $W(k)$ if $A$ is ordinary (Norman-Oort) or if $A$ is an elliptic curve (lift the cubic equation defining it).

1). In general, we don't expect to lift $A$ to $W(k)$. But can we always lift $A$ to some ring of integers $\mathcal{O}_K$, where $K/\mathbb{Q}_p$$K/W(k)$ is a finite extension? (Such an extension must be totally ramified to ensure a surjection $K \to k$).

2). If not, is there data internal to $A$ that tells us about when such lifts do exist, analogous to $$\text{Ordinary } \implies \text{lifts to $W(k)$}?$$

Assume I have an abelian variety $A$ over a finite field $k$ of characteristic $p$. Work of Norman and Oort (1980) says I can lift $A$ to an abelian variety $\mathscr{A}$ over some characteristic zero ring $R$ with a surjective morphism $R \to k$.

In fact, we can lift $A$ to the Witt ring $W(k)$ if $A$ is ordinary (Norman-Oort) or if $A$ is an elliptic curve (lift the cubic equation defining it).

1). In general, we don't expect to lift $A$ to $W(k)$. But can we always lift $A$ to some ring of integers $\mathcal{O}_K$, where $K/\mathbb{Q}_p$ is a finite extension?

2). If not, is there data internal to $A$ that tells us about when such lifts do exist, analogous to $$\text{Ordinary } \implies \text{lifts to $W(k)$}?$$

Assume I have an abelian variety $A$ over a finite field $k$ of characteristic $p$. Work of Norman and Oort (1980) says I can lift $A$ to an abelian variety $\mathscr{A}$ over some characteristic zero ring $R$ with a surjective morphism $R \to k$.

In fact, we can lift $A$ to the Witt ring $W(k)$ if $A$ is ordinary (Norman-Oort) or if $A$ is an elliptic curve (lift the cubic equation defining it).

1). In general, we don't expect to lift $A$ to $W(k)$. But can we always lift $A$ to some ring of integers $\mathcal{O}_K$, where $K/W(k)$ is a finite extension? (Such an extension must be totally ramified to ensure a surjection $K \to k$).

2). If not, is there data internal to $A$ that tells us about when such lifts do exist, analogous to $$\text{Ordinary } \implies \text{lifts to $W(k)$}?$$

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John Binder
  • 1.5k
  • 9
  • 14

Lifting Abelian Varieties to p-adic fields

Assume I have an abelian variety $A$ over a finite field $k$ of characteristic $p$. Work of Norman and Oort (1980) says I can lift $A$ to an abelian variety $\mathscr{A}$ over some characteristic zero ring $R$ with a surjective morphism $R \to k$.

In fact, we can lift $A$ to the Witt ring $W(k)$ if $A$ is ordinary (Norman-Oort) or if $A$ is an elliptic curve (lift the cubic equation defining it).

1). In general, we don't expect to lift $A$ to $W(k)$. But can we always lift $A$ to some ring of integers $\mathcal{O}_K$, where $K/\mathbb{Q}_p$ is a finite extension?

2). If not, is there data internal to $A$ that tells us about when such lifts do exist, analogous to $$\text{Ordinary } \implies \text{lifts to $W(k)$}?$$