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In this paper we prove a duality for constructible sheaves on conically smooth stratified spaces. Here we consider sheaves with values in a stable and bicomplete $\infty$-category equipped with a closed symmetric monoidal structure, and in…

Algebraic Topology · Mathematics 2023-12-04 Marco Volpe

We construct a spectral sequence associated to a stratified space, which computes the compactly supported cohomology groups of an open stratum in terms of the compactly supported cohomology groups of closed strata and the reduced cohomology…

Algebraic Topology · Mathematics 2017-06-14 Dan Petersen

In this paper, we investigate a sheaf-theoretic interpretation of stratification learning from geometric and topological perspectives. Our main result is the construction of stratification learning algorithms framed in terms of a sheaf on a…

Computational Geometry · Computer Science 2020-06-12 Adam Brown , Bei Wang

We extend Orlov's representability theorem on the equivalence of derived categories of sheaves to the case of smooth stacks associated to normal projective varieties with only quotient singularities.

Algebraic Geometry · Mathematics 2007-05-23 Yujiro Kawamata

We study the cohomology theory of sheaf complexes for open embeddings of topological spaces and related subjects. The theory is situated in the intersection of the general Cech theory and the theory of derived categories. That is to say, on…

Algebraic Topology · Mathematics 2018-10-16 Tatsuo Suwa

For a finite dimensional vector space V of dimension n, we consider the incidence correspondence (or partial flag variety) X in P(V) x P(V*), parametrizing pairs consisting of a point and a hyperplane containing it. We completely…

Algebraic Geometry · Mathematics 2022-10-10 Zhao Gao , Claudiu Raicu

We introduce a theory of stratifications of noncommutative stacks (i.e. presentable stable $\infty$-categories), and we prove a reconstruction theorem that expresses them in terms of their strata and gluing data. This reconstruction theorem…

Algebraic Geometry · Mathematics 2023-11-10 David Ayala , Aaron Mazel-Gee , Nick Rozenblyum

We prove that the derived direct image of the constant sheaf with field coefficients under any proper map with smooth source contains a canonical summand. This summand, which we call the geometric extension, only depends on the generic…

Representation Theory · Mathematics 2023-09-22 Chris Hone , Geordie Williamson

This thesis develops the theory of sheaves and cosheaves with an eye towards applications in science and engineering. To provide a theory that is computable, we focus on a combinatorial version of sheaves and cosheaves called cellular…

Algebraic Topology · Mathematics 2014-12-18 Justin Curry

For a singular variety X, an essential step to determine its smoothability and study its deformations is the understanding of the tangent sheaf and of the sheaf T^1_X:=ext^1(Omega_X,O_X). A variety is semi-smooth if its singularities are…

Algebraic Geometry · Mathematics 2021-05-05 Barbara Fantechi , Marco Franciosi , Rita Pardini

Let $X$ be a smooth variety over an algebraically closed field $k$ of positive characteristic, ${\rm D}_X$ the sheaf of PD-differential operators, and ${\bar D}_X$ its central reduction, the sheaf of small differential operators. In this…

Algebraic Geometry · Mathematics 2010-03-10 Alexander Samokhin

A classical result of A. Connes asserts that the Frechet algebra of smooth functions on a smooth compact manifold X provides, by a purely algebraic procedure, the de Rham cohomology of X. Namely the procedure uses Hochschild and cyclic…

alg-geom · Mathematics 2008-02-03 Jean-Paul Brasselet , André Legrand

The goal of this article is to extend a theorem of Lurie \[ \mathsf{Sh}_A (X) = \mathsf{Fun}(\mathsf{Exit}_A (X), \mathsf{S}) \] representing constructible sheaves with values in $ \mathsf{S} $, the $ \infty $-category of spaces, on a…

Algebraic Topology · Mathematics 2021-02-25 Damien Lejay

We explicitly describe cohomology of the sheaf of differential forms with poles along a semiample divisor on a complete simplicial toric variety. As an application, we obtain a new vanishing theorem which is an analogue of the…

Algebraic Geometry · Mathematics 2007-05-23 Anvar Mavlyutov

We interpret some results of persistent homology and barcodes (in any dimension) with the language of microlocal sheaf theory. For that purpose we study the derived category of sheaves on a real finite-dimensional vector space V. By using…

Algebraic Topology · Mathematics 2018-09-10 Masaki Kashiwara , Pierre Schapira

This paper is about sheaf cohomology for varieties (schemes) in characteristic $p>0$. We assume the presence of a Frobenius splitting. (See V.B. Mehta and A. Ramanathan, Frobenius splitting and cohomology vanishing for Schubert varieties,…

alg-geom · Mathematics 2009-10-22 V. B. Mehta , Wilberd van der Kallen

Torsion sensitive intersection homology was introduced to unify several versions of Poincare duality for stratified spaces into a single theorem. This unified duality theorem holds with ground coefficients in an arbitrary PID and with no…

Geometric Topology · Mathematics 2023-09-27 Greg Friedman

We study the relationship between the equations defining a projective variety and properties of its secant varieties. In particular, we use information about the syzygies among the defining equations to derive smoothness and normality…

Algebraic Geometry · Mathematics 2007-05-23 Peter Vermeire

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…

Algebraic Geometry · Mathematics 2014-08-15 Elmar Grosse-Klönne

Given an open-closed decomposition of the stratifying poset, we construct a new semi-orthogonal decomposition of the $\infty$-category of constructible sheaves on a stratified space admitting an exit-path $\infty$-category. From this we…

K-Theory and Homology · Mathematics 2026-02-24 Qingyuan Bai , Peter J. Haine