On the connected components of moduli spaces of finite flat models

Ramification and moduli spaces of finite flat models

We determine the type of the zeta functions and the range of the dimensions of the moduli spaces of finite flat models of two-dimensional local Galois representations over finite fields. This gives a generalization of Raynaud's theorem on the uniqueness of finite flat models in low ramifications.

Connectedness of The Moduli Space of Artin-Schreier Curves of Fixed Genus

We study the moduli space $\mathcal{AS}_{g}$ of Artin-Schreier curves of genus $g$ over an algebraically closed field $k$ of positive characteristic $p$. The moduli space is partitioned by irreducible strata, where each stratum parameterizes Artin-Schreier curves whose ramification divisors have the same coefficients. We construct deformations of these curves to study the relations between those strata. As an application, when $p=3$, we prove that $\mathcal{AS}_{g}$ is connected for all possible $g$. When $p>3$, it turns out that $\mathcal{AS}_{g}$ is connected for sufficiently large value of …

Connected components of moduli stacks of torsors via Tamagawa numbers

Let $X$ be a smooth projective geometrically connected curve over a finite field with function field $K$. Let $\G$ be a connected semisimple group scheme over $X$. Under certain hypothesis we prove the equality of two numbers associated with $\G$. The first is an arithmetic invariant, its Tamagawa number. The second, is a geometric invariant, the number of connected components of the moduli stack of $\G$-torsors on $X$.

The absolute Galois group acts faithfully on the connected components of the moduli space of surfaces of general type

We show that the Galois group $Gal(\bar{\Q} /\Q)$ operates faithfully on the set of connected components of the moduli spaces of surfaces of general type, and also that for each element $σ\in Gal(\bar{\Q} /\Q)$ different from the identity and from complex conjugation, there is a surface of general type such that $X$ and the Galois conjugate variety $X^σ$ have nonisomorphic fundamental groups. The result was announced by the second author at the Alghero Conference 'Topology of algebraic varieties' in september 2006. Before the present paper was actually written, we received a very interesting p…

关于p-adic shtukas模空间与局部Shimura簇的几何连通分支

On the geometric connected components of moduli spaces of p-adic shtukas and local Shimura varieties

本文研究了p-adic shtukas模空间与局部Shimura簇的拓扑性质，构造了特殊化映射，并在HN-不可约条件下确定了无限层级模空间的几何连通分支，证明了Rapoport和Viehmann猜想的新情形。

L-参数模空间的连通分支

Connected components of the moduli space of L-parameters

本文证明了关于p-adic群的L-参数模空间连通分支与R-表示范畴中块相关的一个强形式猜想，适用于任何Zbar[1/p]上的整环R。