English
Related papers

Related papers: Compatible systems of $\ell$-adic sheaves

200 papers

We extend Langton's valuative criterion for families of coherent algebraic sheaves to a complex analytic set-up. As a consequence we derive a set of sufficient conditions for the compactness of a moduli space of semistable sheaves over a…

Algebraic Geometry · Mathematics 2021-08-30 Matei Toma

For a smooth proper scheme over a local field of mixed characteristics which has semistable reduction we define the category of its semistable etale sheaves and under certain hypothesis we prove the appropriate semistable comparison…

Algebraic Geometry · Mathematics 2012-12-18 Fabrizio Andreatta , Adrian Iovita

We prove a twist formula for the epsilon factor of a constructible sheaf on a projective smooth variety over a finite field in terms of characteristic class of the sheaf. This formula is a modified version of the formula conjectured by Kato…

Algebraic Geometry · Mathematics 2018-03-19 Naoya Umezaki , Enlin Yang , Yigeng Zhao

We prove a number of results on the \'etale cohomology of rigid analytic varieties over $p$-adic non-archimedean local fields. Among other things, we establish bounds for Frobenius eigenvalues, show a strong version of Grothendieck's local…

Algebraic Geometry · Mathematics 2025-07-21 David Hansen , Bogdan Zavyalov

We prove a theorem on how a conclusion on homological dimension of a family of coherent sheaves over a scheme can be done from homological dimension of the restriction of this family to the reduction of the base.

Algebraic Geometry · Mathematics 2014-12-09 Nadezda V. Timofeeva

The aim of this book is to show that the use of f-analytic families of finite type cycles (cycles having finitely many irreducible components, but not compact in general) in a given complex space may be useful in complex geometry, despite…

Algebraic Geometry · Mathematics 2023-05-23 Daniel Barlet , Jon Ingolfur Magnusson

We introduce a notion of complexity of a complex of ell-adic sheaves on a quasi-projective variety and prove that the six operations are "continuous", in the sense that the complexity of the output sheaves is bounded solely in terms of the…

Algebraic Geometry · Mathematics 2022-04-28 W. Sawin , A. Forey , J. Fresán , E. Kowalski

A cycle is algebraically trivial if it can be exhibited as the difference of two fibers in a family of cycles parameterized by a smooth scheme. Over an algebraically closed field, it is a result of Weil that it suffices to consider families…

Algebraic Geometry · Mathematics 2020-02-27 Jeff Achter , Sebastian Casalaina-Martin , Charles Vial

We give explicit criteria of solvability for families of linear systems on time scales. We introduce a new method of embedding a time scale into a non-autonomous system of ODEs. This will be the first step to implementing the structural…

Dynamical Systems · Mathematics 2022-03-31 Sergey Kryzhevich

We discuss a systematic procedure for categorifying presentable six-functor formalisms. Our main result produces, given the input of a representation of the $\infty$-category of correspondences of an $\infty$-category with finite limits…

Algebraic Geometry · Mathematics 2025-11-13 Germán Stefanich

It is a fundamental property of the Chow groups of algebraic schemes that they are contra-functorial with respect to flat morphisms between schemes. While the pullback homomorphism is easy to define at the level of algebraic cycles, the…

Algebraic Geometry · Mathematics 2022-01-25 Nitin Nitsure

Motivated by applications to the categorical and geometric local Langlands correspondences, we establish an equivalence between the category of filtered $\mathcal{D}$-modules on a smooth stack $X$ and the category of $S^1$-equivariant…

Algebraic Geometry · Mathematics 2023-04-21 Harrison Chen

This is a quick survey on the characteristic varieties associated to rank one local systems on a smooth, irreducible, quasi-projective complex variety $M$. A key new result is Proposition 1.8, giving additional information on the…

Algebraic Geometry · Mathematics 2007-05-23 Alexandru Dimca

We study a notion of total acyclicity for complexes of flat sheaves over a scheme. It is Zariski-local - i.e. it can be verified on any open affine covering of the scheme - and it agrees, in their setting, with the notion studied by Murfet…

Commutative Algebra · Mathematics 2016-06-24 Lars Winther Christensen , Sergio Estrada , Alina Iacob

To a smooth and proper morphism $\mathcal{X}\to U$ with quasicompact semiseparated target we associate a sheaf in the \'etale topology, which takes an affine $U$-scheme $V$ to the set of $V$-linear semiorthogonal decompositions (of fixed…

Algebraic Geometry · Mathematics 2025-11-17 Pieter Belmans , Shinnosuke Okawa , Andrea T. Ricolfi

Recently, the singular support and the characteristic cycle of an \'etale sheaf on a smooth variety over a perfect field are constructed by Beilinson and Saito, respectively. In this article, we extend the singular support to a relative…

Algebraic Geometry · Mathematics 2017-02-23 Haoyu Hu , Enlin Yang

We confirm the quasi-projective case of Saito's conjecture, namely that the cohomological characteristic classes defined by Abbes and Saito can be computed in terms of the characteristic cycles. We construct a cohomological characteristic…

Algebraic Geometry · Mathematics 2025-02-18 Enlin Yang , Yigeng Zhao

We define the notion of a sheaf over a complex of groups. As an application, we give a criterion for the developability of a complex of groups. When the developability is witnessed by a morphism to $\mathrm{GL}(V)$ for some $V$, our…

Group Theory · Mathematics 2022-02-15 Joshua L. Faber

We present a uniform theory of constructible sheaves on arbitrary schemes with coefficients in topological or even condensed rings. This is accomplished by defining lisse sheaves to be the dualizable objects in the derived infinity-category…

Algebraic Geometry · Mathematics 2023-05-30 Tamir Hemo , Timo Richarz , Jakob Scholbach

We give a new geometric construction of the big projective module in the principal block of the BGG category $\mathscr{O}$, or rather the corresponding $\mathscr{D}$-module on the flag variety. Namely, given a one-parameter family of…

Representation Theory · Mathematics 2016-08-23 Justin Campbell