伽马函数、单值化与弗罗贝尼乌斯常数

Determining monodromy groups of abelian varieties

Associated to an abelian variety over a number field are several interesting and related groups: the motivic Galois group, the Mumford-Tate group, $\ell$-adic monodromy groups, and the Sato-Tate group. Assuming the Mumford-Tate conjecture, we show that from two well chosen Frobenius polynomials of our abelian variety, we can recover the identity component of these groups (or at least an inner form), up to isomorphism, along with their natural representations. We also obtain a practical probabilistic algorithm to compute these groups by considering more and more Frobenius polynomials; the group…

半稳定曲线上的 p-adic 迭代积分

p-adic iterated integration on semistable curves

本文以幂零对数刚性基本群重构半稳定曲线上的 p-adic 迭代积分，借助 Frobenius 不变量与对偶图阐明 Berkovich–Coleman 积分，并将 Vologodsky 积分解释为沿组合典范路径的积分。

椭圆曲线族的 Frobenius 常数

Frobenius constants for families of elliptic curves

本文研究代数几何中描述 Frobenius 解单值性的 Frobenius 常数，将其表示为模形式的迭代积分，并利用模形式周期理论以 zeta 值表达了部分常数。

Frobenius map and the $p$-adic Gamma function

In this note we study the relationship between the power series expansion of the Dwork exponential and the Mahler expansion of the $p$-adic Gamma function. We exploit this relationship to prove that certain quantities that appeared in our previous computations of the Frobenius map can be expressed in terms of the derivatives of the $p$-adic Gamma function at 0. This is used to prove a conjecture about the non-trivial off-diagonal entry in the Frobenius matrix of the mirror quintic threefold.

p-adic Gamma function and traces of Frobenius of elliptic curves

In \cite{mccarthy2}, McCarthy defined a function $_{n}G_{n}[\cdots]$ using Teichmüller character of finite fields and quotients of $p$-adic gamma function, and expressed the trace of Frobenius of elliptic curves in terms of special values of $_{2}G_{2}[\cdots]$. We establish two different expressions for the traces of Frobenius of elliptic curves in terms of the function $_{2}G_{2}[\cdots]$. As a result, we obtain two relations between special values of the function $_{2}G_{2}[\cdots]$ with different parameters.

The trace of Frobenius of elliptic curves and the $p$-adic gamma function

We define a function in terms of quotients of the $p$-adic gamma function which generalizes earlier work of the author on extending hypergeometric functions over finite fields to the $p$-adic setting. We prove, for primes $p > 3$, that the trace of Frobenius of any elliptic curve over $\mathbb{F}_p$, whose $j$-invariant does not equal 0 or 1728, is just a special value of this function. This generalizes results of Fuselier and Lennon which evaluate the trace of Frobenius in terms of hypergeometric functions over $\mathbb{F}_p$ when $p \equiv 1 \pmod {12}$.

Galois groups arising from families with big orthogonal monodromy

We study the Galois groups of polynomials arising from a compatible family of representations with big orthogonal monodromy. We show that the Galois groups are usually as large as possible given the constraints imposed on them by a functional equation and discriminant considerations. As an application, we consider the Frobenius polynomials arising from the middle étale cohomology of hypersurfaces in $\mathbb{P}_{\mathbb{F}_q}^{2n+1}$ of degree at least $3$. We also consider the $L$-functions of quadratic twists of fixed degree of an elliptic curve over a function field $\mathbb{F}_q(t)$. To de…

Unipotent extensions and differential equations (after Bloch-Vlasenko)

S. Bloch and M. Vlasenko recently introduced a theory of \emph{motivic Gamma functions}, given by periods of the Mellin transform of a geometric variation of Hodge structure, which they tie to the monodromy and asymptotic behavior of certain unipotent extensions of the variation. Here we further examine these Gamma functions and the related \emph{Apéry and Frobenius invariants} of a VHS, and establish a relationship to motivic cohomology and solutions to inhomogeneous Picard-Fuchs equations.

Geometric Gamma values and zeta values in positive characteristic

In analogy with values of the classical Euler Gamma-function at rational numbers and the Riemann zeta-function at positive integers, we consider Thakur's geometric Gamma-function evaluated at rational arguments and Carlitz zeta-values at positive integers. We prove that, when considered together, all of the algebraic relations among these special values arise from the standard functional equations of the Gamma-function and from the Euler-Carlitz relations and Frobenius p-th power relations of the zeta-function.

The Gamma conjecture for $G$-functions

The Bombieri-Dwork conjecture predicts that the differential equations satisfied by $G$-functions come from geometry. In this paper, we will look at special $G$-functions whose differential equations have a special singularity with maximally unipotent monodromy. We will formulate a Gamma conjecture about such $G$-functions, which has close connections with the mirror symmetry of Calabi-Yau threefolds and the Gamma conjecture in algebraic geometry. We will provide examples to support this conjecture, which involves numerical computations using Mathematica programs.

Algébricité modulo p, séries hypergéométriques et structures de Frobenius forte

This work is devoted to study of algebraicty modulo p of Siegel's G-functions. Our goal is to emphasize the relevance of the notion of strong Frobenius structure, clasically studied in the theory of the p-adic diffenrential equations, for the study of a Adamczewski-Delaygue's conjecture concerning of the degree of algebraicity modulo p of G-functions. For this, we first make a Christol's result explicit by showing that if $f$ is a G-function that is solution of a differential operator $L$ in $ \mathbb{Q}(z)[d/dz]$ of order $n$ endowed of a strong Frobenius structure of period $h$ for the prime…

超几何方程上的弗罗贝尼乌斯结构，p进polygamma值与p进L值

Frobenius structure on hypergeometric equations, p-adic polygamma values and p-adic L-values

本文研究了超几何方程上的弗罗贝尼乌斯结构，通过p进polygamma函数推广了Kedlaya的公式，并将其与p进L值联系起来，应用于p进上同调的研究。

On p-adic Frobenius lifts and p-adic periods, from a Deformation Theory viewpoint

Presenting p-adic numbers as {\em deformations} of finite fields allows a better understanding of Frobenius lifts and their connection with p-derivations in the sense of Buium \cite{Buium-Main}. In this way "numbers {\em are} functions", as recognized before \cite{Manin:Numbers}, allowing to view initial structure deformation problems as arithmetic differential equations as in \cite{Buium-Manin}, and providing a cohomological interpretation to Buium calculus via Hochschild cohomology which controls deformations of algebraic structures. Applications to p-adic periods are considered, including t…

Maximal Unipotent Monodromy, congruences "à la Lucas" and Algebraic independence

Let $f(z)$ be in $1+z\mathbb{Q}[[z]]$ and $\mathcal{S}$ be an infinite set of prime numbers such that, for all $p\in\mathcal{S}$, we can reduce $f(z)$ modulo $p$. We let $f(z)_{\mid p}$ denote the reduction of $f(z)$ modulo $p$. Generally, when $f(z)$ is D-finite, $f(z)_{\mid p}$ is algebraic over $\mathbb{F}_p(z)$. It turns out that if $f(z)$ is a solution of a polynomial of the form $X-A_p(z)X^{p^l}$, we can use this type of equations to obtain results of transcendence and algebraic independence over $\mathbb{Q}(z)$. In the present paper, we look for conditions on the differential operators …

Local constancy for the reduction mod p of 2-dimensional crystalline representations

Irreducible crystalline representations of dimension 2 of Gal(Qpbar/Qp) depend up to twist on two parameters, the weight k and the trace of frobenius a_p. We show that the reduction modulo p of such a representation is a locally constant function of a_p (with an explicit radius) and a locally constant function of the weight k if a_p <> 0. We then give an algorithm for computing the reductions modulo p of these representations. The main ingredient is Fontaine's theory of (phi,Gamma)-modules as well as the theory of Wach modules.