The six operations for sheaves on Artin stacks II: Adic Coefficients

Decomposition Theorem for Perverse sheaves on Artin stacks over finite fields

We generalize the decomposition theorem for perverse sheaves to Artin stacks with affine stabilizers over finite fields.

单值化 ℓ-adic 层的傅里叶变换与特征循环

The Fourier Transform and Characteristic Cycles of Monodromic $\ell$-adic Sheaves

本文将 Brylinski–Malgrange 关于单值化代数 D-模傅里叶变换保持特征循环的经典结果推广到 ℓ-adic 层范畴，建立了 ℓ-adic 语境下的精确类比。

Deformations and Rigidity of $\ell$-adic Sheaves

Let $X$ be a smooth connected projective algebraic curve over an algebraically closed field, and let $S$ be a finite nonempty closed subset in $X$. We study deformations of $\overline{\mathbb F}_\ell$-sheaves. The universal deformation space is a formal scheme. Its generic fiber has a rigid analytic space structure. By studying this rigid analytic space, we prove a conjecture of Katz which says that if a lisse $\overline{\mathbb Q}_\ell$-sheaf $\mathcal F$ on $X-S$ is irreducible and rigid, then we have $\mathrm{dim}\, H^1(X,j_\ast\mathcal End(\mathcal F))=2g$, where $j:X-S\to X$ is the open i…

反常层的导出模空间

The derived moduli of perverse sheaves

本文构造了参数化复代数簇和紧实解析簇上可构造层的导出Artin叠，并证明每个反常函数给出反常层的开子叠，推广了通常的特征叠，作为应用构造了与穿孔Riemann曲面相关的上同调Hall代数的新例子。

Explicit local multiplicative convolution of l-adic sheaves

We give explicit formulas for the local multiplicative convolution functors which express the local monodromies of the convolution of two $\ell$-adic sheaves on the torus ${\mathbb G}_m$ over the algebraic closure of a finite field in terms of the local monodromies of the factors.

p-adic and motivic measure on Artin n-stacks

We construct a notion of p-adic measure on Artin n-stacks which are strongly of finite type over the ring of p-adic integers. We also prove the rationality of of the Poincare series and the Serre series associated with such stacks. Finally, we use motivic integration to show that the rationality of the Serre series is uniform with respect to p.

An effective criterion for finite monodromy of $\ell$-adic sheaves

We provide an effective version of Katz' criterion for finiteness of the monodromy group of a lisse, pure of weight zero, $\ell$-adic sheaf on a normal variety over a finite field, depending on the numerical complexity of the sheaf

Nearby slopes and boundedness for $\ell$-adic sheaves in positive characteristic

The goal of this paper is to motivate a boundedness conjecture on nearby slopes of $\ell$-adic sheaves in positive characteristic, and to prove it for smooth curves. For a constructible $\ell$-adic sheaf, we prove the finiteness of the set of nearby slopes associated to a given morphism. For the constant sheaf, we prove the vanishing of nearby slopes in case of generalized semi-stable reduction.

关于叶状复解析结构形变 II：Artin环函子

On deformations of foliated complex analytic structures II: Functors of Artin rings

本文以Artin环函子为框架，研究叶状非奇异簇的形变，识别一阶形变与障碍。

Artin 反常层

Artin perverse sheaves

本文研究 Artin ℓ-adic 复形上反常 t-结构的存在性，证明在维数小于2的优概型上成立并给出三维反例，进而在有限域有限型概型上构造反常同伦 t-结构，刻画其单对象并证明无权截断函子的 t-正合性。

Deformation of $\ell$-adic sheaves with Undeformed Local Monodromy

Let $X$ be a smooth connected algebraic curve over an algebraically closed field $k$. We study the deformation of $\ell$-adic Galois representations of the function field of $X$ while keeping the local Galois representations at all places undeformed.

Wild ramification, the nearby cycle complexes, and the characteristic cycles of $\ell$-adic sheaves

We prove a purely local form of a result of Saito and Yatagawa. They proved that the characteristic cycle of a constructible étale sheaf is determined by wild ramification of the sheaf along the boundary of a compactification. But they had to consider ramification at all the points of the compactification. We give a pointwise result, that is, we prove that the characteristic cycle of a constructible étale sheaf around a point is determined by wild ramification at the point. The key ingredient is to prove that wild ramification of the stalk of the nearby cycle complex of a constructible étale s…

Generic Base Change, Artin's Comparison Theorem, and the Decomposition Theorem for Complex Artin stacks

We prove the generic base change theorem for stacks, and give an exposition on the lisse-analytic topos of complex analytic stacks, proving some comparison theorems between various derived categories of complex analytic stacks. This enables us to deduce the decomposition theorem for perverse sheaves on complex Artin stacks with affine stabilizers from the case over finite fields.

On the relative twist formula of $\ell$-adic sheaves

We propose a conjecture on the relative twist formula of $\ell$-adic sheaves, which can be viewed as a generalization of Kato-Saito's conjecture. We verify this conjecture under some transversal assumptions. We also define a relative cohomological characteristic class and prove that its formation is compatible with proper push-forward. A conjectural relation is also given between the relative twist formula and the relative cohomological characteristic class.

Local convolution of l-adic sheaves on the torus

For K and L two l-adic perverse sheaves on the one-dimensional torus over the algebraic closure of a finite field, we show that the local monodromies of their convolution K*L at its points of non-smoothness is completely determined by the local monodromies of K and L. This generalizes a previous result of N. Katz for the case where K and L are smooth, tame at 0 and totally wild at infinity.

Compatible systems of $\ell$-adic sheaves

We introduce a notion of compatibility for families $(\mathcal{F}_{\ell})_{\ell}$ of bounded constructible $\ell$-adic complexes of étale sheaves on schemes. For schemes of finite type over a field, this notion is preserved by the usual six functors. We prove that the compatibility of a family is preserved by the nearby cycles functor and by the linearized $\varepsilon$-factors introduced recently by the author. We establish independence of $\ell$ for the characteristic cycles and characteristic $\varepsilon$-cycles of compatible families.

Tensor and convolution direct image of $\ell$-adic sheaves

Given a Galois étale map of varieties $π:Y\to X$ and an $\ell$-adic sheaf or derived category object $P\in D^b_c(Y,{\mathbb Q}_\ell)$, we study two cohomological operations: the tensor direct image and (in the case of perverse sheaves) the convolution direct image, which give objects of $D^b_c(X,{\mathbb Q}_\ell)$, and can be used to improve the estimates on some partial exponential sums and the number of rational points on certain varieties.

On localizations of the characteristic classes of l-adic sheaves and conductor formula in characteristic p>0

The Grothendieck-Ogg-Shafarevich formula calculates the l-adic Euler-Poincare number of an l-adic sheaf on a curve by an invariant produced by the wild ramification of the l-adic sheaf named Swan class. A. Abbes, K. Kato and T. Saito generalize this formula to any dimensional scheme. In this paper, assuming the strong resolution of singularities we prove a localized version of a formula proved by A. Abbes and T. Saito using the characteristic class of an l-adic sheaf. As an application, we prove a conductor formula in equal characteristic.

$\ell$-adic 层的奇异支集

The singular support of an $\ell$-adic sheaf

本文定义了任意域上光滑簇上 $\ell$-adic 层的奇异支集，通过结合 Beilinson 的挠 étale 层奇异支集构造与 Hansen 和 Scholze 的泛局部非循环性理论实现。

On localizations of characteristic classes of l-adic sheaves of rank 1

The Grothendieck-Ogg-Shafarevich formula is generalized to any dimensional scheme by Abbes-Kato-Saito. In this paper, we introduce two methods of localization of the characteristic classes for sheaves of rank 1 and compare them. As a corollary of this comparison, we obtain a refinement of a formula proved by Abbes-Saito without denominator for a smooth sheaf of rank 1 which is clean with respect to the boundary.

数域上格式的混合合$\ell$-adic复形

Mixed $\ell$-adic complexes for schemes over number fields

本文针对数域上的格式，定义了水平ℓ进复形与周层，并指出混合周层一般无权滤过，通过直接在有权滤过的周层导出范畴中工作，将中间扩张计算方法推广到有限生成域。

Grothendieck rings of Artin n-stacks

We introduce a Grothendieck ring of higher Artin stacks generalizing the Grothendieck ring of algebraic varieties. We show that this ring is not trivial by noticing that it factors the invariant "number of rational points over a finite field". We also introduce the notion of "special Artin stacks", which by definition have affine homotopy groups π_{i}, and furthermore unipotent for i>1. Our principal theorem states that the natural inclusion morphism from the Grothendieck ring of varieties to the Grothendieck ring of special Artin stacks is an isomorphism after inverting the class of the affin…

光滑 $p$-adic 分析 Artin 堆栈的局部结构

Local structure of smooth \texorpdfstring{$p$}{p}-adic analytic Artin stacks

本文证明了光滑 $p$-adic 分析 Artin 堆栈的局部轻质-紧致结构，并展示了其 $!$-good 性。

Constructibility and Reflexivity in non-Archimedean geometry

We introduce a notion of constructibility for étale sheaves with torsion coefficients over a suitable class of adic spaces. This notion is related to the classical notion of constructibility for schemes via the nearby cycles functor. We use the work of R. Huber to define an adic Verdier dual and investigate the extent to which we have a 6-functor formalism in this context. Lastly, we attempt to classify those sheaves which are reflexive with respect to the adic Verdier dual.

$p$-adic Hodge theory for Artin stacks

This work is devoted to the study of integral $p$-adic Hodge theory in the context of Artin stacks. For a Hodge-proper stack, using the formalism of prismatic cohomology, we establish a version of $p$-adic Hodge theory with the étale cohomology of the Raynaud generic fiber as an input. In particular, we show that the corresponding Galois representation is crystalline and that the associated Breuil-Kisin module is given by the prismatic cohomology. An interesting new feature of the stacky setting is that the natural map between étale cohomology of the algebraic and the Raynaud generic fibers is…

Sheaves of bounded $p$-adic logarithmic differential forms

Let $K$ be a local field, $X$ the Drinfel'd symmetric space $X$ of dimension $d$ over $K$ and ${\mathfrak X}$ the natural formal ${\mathcal O}_K$-scheme underlying $X$; thus $G={\rm GL}\sb {d+1}(K)$ acts on $X$ and ${\mathfrak X}$. Given a $K$-rational $G$-representation $M$ we construct a $G$-equivariant subsheaf ${\mathcal M}^0_{{\mathcal O}_{\dot{K}}}$ of ${\mathcal O}_K$-lattices in the constant sheaf $M$ on ${\mathfrak X}$. We study the cohomology of sheaves of logarithmic differential forms on $X$ (or ${\mathfrak X}$) with coefficients in ${\mathcal M}^0_{{\mathcal O}_{\dot{K}}}$. In the…

p-adic Cauchy定理与超收敛周期层

The p-adic Cauchy Theorem and Overconvergent Period Sheaves

本文建立了任意光滑刚性解析流形上p-adic Cauchy定理的几何类比，证明超收敛de Rham周期结构层的水平截面函子与Scholze的OBdR水平截面函子一致，并应用于识别D-cap-模的de Rham函子。

On continuity of local epsilon factors of $\ell$-adic sheaves

Let $S$ be a noetherian scheme and $f\colon X\to S$ be a smooth morphism of relative dimension 1. For a locally constant sheaf on the complement of a divisor in $X$ at over $S$, Deligne and Laumon proved that the universal local acyclicity is equivalent to the local constancy of Swan conductors. In this article, assuming the universal local acyclicity, we show an analogous result of the continuity of local epsilon factors. We also give a generalization of this result to a family of isolated singularities.

$p$-adic estimates of abelian Artin $L$-functions on curves

The purpose of this article is to prove a "Newton over Hodge" result for finite characters on curves. Let $X$ be a smooth proper curve over a finite field $\mathbb{F}_q$ of characteristic $p\geq 3$ and let $V \subset X$ be an affine curve. Consider a nontrivial finite character $ρ:π_1^{et}(V) \to \mathbb{C}^\times$. In this article, we prove a lower bound on the Newton polygon of the $L$-function $L(ρ,s)$. The estimate depends on monodromy invariants of $ρ$: the Swan conductor and the local exponents. Under certain nondegeneracy assumptions this lower bound agrees with the irregular Hodge filt…

Artin-Tate motivic sheaves with finite coefficients over an algebraic variety

We propose a construction of a tensor exact category F_X^m of Artin-Tate motivic sheaves with finite coefficients Z/m over an algebraic variety X (over a field K of characteristic prime to m) in terms of etale sheaves of Z/m-modules over X. Among the objects of F_X^m, in addition to the Tate motives Z/m(j), there are the cohomological relative motives with compact support M_cc^m(Y/X) of varieties Y quasi-finite over X. Exact functors of inverse image with respect to morphisms of algebraic varieties and direct image with compact supports with respect to quasi-finite morphisms of varieties Y\to …

A Tauberian Theorem for $\ell$-adic Sheaves on $\mathbb A^1$

Let $K\in L^1(\mathbb R)$ and let $f\in L^\infty(\mathbb R)$ be two functions on $\mathbb R$. The convolution $$(K\ast f)(x)=\int_{\mathbb R}K(x-y)f(y)dy$$ can be considered as an average of $f$ with weight defined by $K$. Wiener's Tauberian theorem says that under suitable conditions, if $$\lim_{x\to \infty}(K\ast f)(x)=\lim_{x\to \infty} (K\ast A)(x)$$ for some constant $A$, then $$\lim_{x\to \infty}f(x)=A.$$ We prove the following $\ell$-adic analogue of this theorem: Suppose $K,F, G$ are perverse $\ell$-adic sheaves on the affine line $\mathbb A$ over an algebraically closed field of chara…

$p$-adic sheaves on classifying stacks, and the $p$-adic Jacquet-Langlands correspondence

We establish several new properties of the $p$-adic Jacquet-Langlands functor defined by Scholze in terms of the cohomology of the Lubin-Tate tower. In particular, we reprove Scholze's basic finiteness theorems, prove a duality theorem, and show a kind of partial Künneth formula. Using these results, we deduce bounds on Gelfand-Kirillov dimension, together with some new vanishing and nonvanishing results. Our key new tool is the six functor formalism with solid almost $\mathcal{O}^+/p$-coefficients developed recently by the second author [Man22]. One major point of this paper is to extend the …

Wall crossing for derived categories of moduli spaces of sheaves on rational surfaces

We remove the global quotient presentation input in the theory of windows in derived categories of smooth Artin stacks of finite type. As an application, we use existing results on flipping of strata for wall-crossing of Gieseker semi-stable torsion-free sheaves of rank two on rational surfaces to produce semi-orthogonal decompositions relating the different moduli stacks. The complementary pieces of these semi-orthogonal decompositions are derived categories of products of Hilbert schemes of points on the surface.

Artin消没定理在阿贝尔簇的$\ell$-adic塔上的成立

Artin vanishing along the $\ell$-adic tower of an abelian variety

本文证明阿贝尔簇上可构造$\mathbb{F}_{\ell}$-层沿$\ell$-adic塔的Artin消没，回答Bhatt--Schnell--Scholze问题，并给出Fourier--Mellin变换上同调层的余维数估计，推广Esnault--Kerz结果。

Mixed sheaves on Shimura varieties and their higher direct images in toroidal compactifications

Let (P,X) be Shimura data, M=M(P,X,K) the Shimura variety of level K. To an algebraic representation of P, one can associate a mixed sheaf (variation of Hodge structure, l-adic sheaf) on M. In the paper, we study the degeneration of such sheaves along strata in toroidal compactifications of M. The main result (2.8 in the Hodge setting, 3.9 in the l-adic setting) gives a formula for this degeneration in terms of Hochschild cohomology of certain unipotent subgroups of P. The new version differs from the earlier one in that the proof of 2.8 was rewritten. In particular, the effect of Saito's spec…

Sur la cohomologie étale de la courbe de Fargues-Fontaine

In this article the étale cohomology of constructible torsion sheaves on the étale site of the algebraic resp. adic Fargues-Fontaine curve is analyzed. In the $\ell\neq p$-torsion case, two conjectures of Fargues are verified: vanishing in degrees greater than two and the comparison between the étale cohomology of the adic and the algebraic curve. In the $p$-torsion case, under a certain assumption, the vanishing of the étale cohomology in degrees greater than two of those Zariski-constructible sheaves on the adic curve that come via pullback from the algebraic curve is proven.

From the function-sheaf dictionary to quasicharacters of $p$-adic tori

We consider the rigid monoidal category of character sheaves on a smooth commutative group scheme $G$ over a finite field $k$ and expand the scope of the function-sheaf dictionary from connected commutative algebraic groups to this setting. We find the group of isomorphism classes of character sheaves on $G$ and show that it is an extension of the group of characters of $G(k)$ by a cohomology group determined by the component group scheme of $G$. We also classify all morphisms in the category character sheaves on $G$. As an application, we study character sheaves on Greenberg transforms of loc…

ℓ-adic sheaves on varieties 的特征epsilon cycles

Characteristic Epsilon Cycles of $\ell$-adic Sheaves on Varieties

本文研究了ℓ-adic sheaves的特征epsilon cycles，提出了一种基于奇异支撑的循环，并证明了其满足Milnor型公式，同时给出了全局epsilon因子的乘积公式及一般完美域上的推广。

Tangent Lie algebra of derived Artin stacks

Since the work of Mikhail Kapranov in [Kap], it is known that the shifted tangent complex $\mathbb{T}_X[-1]$ of a smooth algebraic variety $X$ is endowed with a weak Lie structure. Moreover any complex of quasi-coherent sheaves on $X$ is endowed with a weak Lie action of this tangent Lie algebra. This action is given by the Atiyah class of $E$. We will generalize this result to (finite enough) derived Artin stacks, without any smoothness assumption. This in particular applies to (finite enough) singular schemes. This work uses tools of both derived algebraic geometry and $\infty$-category theo…

p进Cherednik代数在刚性解析空间上的研究

p-adic Cherednik algebras on rigid analytic spaces

本文研究了p进Cherednik代数在刚性空间上的构造及其性质，提出了p进解析版本的Cherednik代数sheaves。

Reciprocity sheaves and their ramification filtrations

We define a motivic conductor for any presheaf with transfers $F$ using the categorical framework developed for the theory of motives with modulus by Kahn-Miyazaki-Saito-Yamazaki. If $F$ is a reciprocity sheaf this conductor yields an increasing and exhaustive filtration on $F(L)$, where $L$ is any henselian discrete valuation field of geometric type over the perfect ground field. We show if $F$ is a smooth group scheme, then the motivic conductor extends the Rosenlicht-Serre conductor; if $F$ assigns to $X$ the group of finite characters on the abelianized étale fundamental group of $X$, then…

凝聚层、剪切D-模与Hochschild上链

Coherent sheaves, sheared D-modules, and Hochschild cochains

本文证明拟光滑概形上的归纳凝聚层范畴与其移位余切丛上的剪切D-模范畴之间存在自然的Morita等价，并推广到拟光滑Artin叠，从而为函数域上非分歧自守函数在算术Arthur参数叠上的局部化提供了精确表述。

动机层的完备化

Completion of motivic sheaves

本文研究动机层的$\u2113$-进完备化，发现其在等特征下与六种运算相容，可重构几何$\u2113$-进层，但混合特征下系统性失效。

Arthur packets for $p$-adic groups by way of microlocal vanishing cycles of perverse sheaves, with examples

In this article we propose a geometric description of Arthur packets for $p$-adic groups using vanishing cycles of perverse sheaves. Our approach is inspired by the 1992 book by Adams, Barbasch and Vogan on the Langlands classification of admissible representations of real groups and follows the direction indicated by Vogan in his 1993 paper on the Langlands correspondence. Using vanishing cycles, we introduce and study a functor from the category of equivariant perverse sheaves on the moduli space of certain Langlands parameters to local systems on the regular part of the conormal bundle for …

整全阿廷动机 II：反常动机与阿廷消失定理

Integral Artin motives II: Perverse motives and Artin Vanishing Theorem

本文研究整系数阿廷平展动机范畴上的反常动机t-结构，构造了近似的反常同伦t-结构，在基概型维数≤2时得到了反常动机t-结构，证明其在维数4时不存在，且依赖于阿廷消失定理的类似结论。

Trivial factors for L-functions of symmetric products of Kloosterman sheaves

We calculate the trivial factors of the L-functions for both finite and p-adic infinite symmetric products of the Kloosterman sheaf.

Calculation of l-adic local Fourier transformations

We calculate the local Fourier transformations for a class of $\bar{\mathbb Q}_\ell$-sheaves. In particular, we verify a conjecture of Laumon and Malgrange. As an application, we calculate the local monodromy of $\ell$-adic hypergeometric sheaves introduced by Katz. We also discuss the characteristic $p$ analogue of the Turrittin-Levelt Theorem for $D$-modules. The method used in this paper can be used to show a conjecture of Ramero which states that the Fourier transformation of an analytic sheaf with meromorphic ramification still has meromorphic ramification.

Relative p-adic Hodge theory, II: Imperfect period rings

In a previous paper, we constructed a category of (phi, Gamma)-modules associated to any adic space over Q_p with the property that the etale (phi, Gamma)-modules correspond to etale Q_p-local systems; these involve sheaves of period rings for Scholze's pro-etale topology. In this paper, we first extend Kiehl's theory of coherent sheaves on rigid analytic spaces to a theory of pseudocoherent sheaves on adic spaces, then construct a corresponding theory of pseudocoherent (phi, Gamma)-modules. We then relate these objects to a more explicit construction in case the space comes equipped with a su…

Moduli spaces of sheaves that are semistable with respect to a Kähler polarisation

Using an existence criterion for good moduli spaces of Artin stacks by Alper-Fedorchuk-Smyth we construct a proper moduli space of rank two sheaves with fixed Chern classes on a given complex projective manifold that are Gieseker-Maruyama-semistable with respect to a fixed Kähler class.

Companions on Artin stacks

Deligne's conjecture that $\ell$-adic sheaves on normal schemes over a finite field admit $\ell'$-companions was proved by L. Lafforgue in the case of curves and by Drinfeld in the case of smooth schemes. In this paper, we extend Drinfeld's theorem to smooth Artin stacks and deduce Deligne's conjecture for coarse moduli spaces of smooth Artin stacks. We also extend related theorems on Frobenius eigenvalues and traces to Artin stacks.

The Étale Homology and The Cycle Maps in Adic Coefficients

In this article, we define the l-adic homology for a morphism of schemes satisfying certain finiteness conditions. This homology has these functors similar to the Chow groups: proper push-forward, flat pull-back, base change, cap-product, etc. In particular on singular varieties, this kind of l-adic homology behaves much better that the classical l-adic cohomology. As an application, we give an much easier approach to construct the cycle maps for arbitrary algebraic schemes over fields of finite cohomology dimension. And we prove these cycle maps kill the algebraic equivalences and commute wit…

BPS不变量来自$p$-adic积分

BPS invariants from $p$-adic integrals

本文通过非阿基米德局部域上的积分定义del Pezzo曲面上1维层模空间的$p$BPS不变量，证明其$\chi$-独立性，并借助Maulik-Shen结果得出与通常BPS不变量的一致性。

概形上的可构造层

Constructible sheaves on schemes

本文在任意概形上以拓扑环或凝聚环为系数建立可构造层的统一理论，将光滑层定义为预平展导出无穷范畴中的可对偶对象，证明其满足预平展下降并构造 t-结构，同时提供系数环操作工具以统一并推广文献中的可构造 ℓ-adic 层理论。

On the essential dimension of coherent sheaves

We characterize all fields of definition for a given coherent sheaf over a projective scheme in terms of projective modules over a finite-dimensional endomorphism algebra. This yields general results on the essential dimension of such sheaves. Applying them to vector bundles over a smooth projective curve C, we obtain an upper bound for the essential dimension of their moduli stack. The upper bound is sharp if the conjecture of Colliot-Thélène, Karpenko and Merkurjev holds. We find that the genericity property proved for Deligne-Mumford stacks by Brosnan, Reichstein and Vistoli still holds for…