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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

We give an explicit construction of the stack of microlocal perverse sheaves on the projective cotangent bundle of a complex manifold. Microlocal perverse sheaves will be represented as complexes of analytic ind-sheaves which have recently…

Algebraic Geometry · Mathematics 2007-05-23 Ingo Waschkies

When $W$ is a finite Coxeter group acting by its reflection representation on $E$, we describe the category ${\mathsf{Perv}}_W(E_{\mathbb C}, {\mathcal{H}}_{\mathbb C})$ of $W$-equivariant perverse sheaves on $E_{\mathbb C}$, smooth with…

Representation Theory · Mathematics 2023-06-22 Martin H. Weissman

We give an explicit combinatorial description of the category Perv(S,N) of perverse sheaves on an oriented surface S (with boundary) with singularities at a given finite set N. The description is given in terms of any spanning graph K in S…

Algebraic Topology · Mathematics 2016-01-11 Mikhail Kapranov , Vadim Schechtman

We give a framework to produce constructible functions from natural functors between categories, without need of a morphism of moduli spaces to model the functor. We show using the Riemann-Hilbert correspondence that any natural (derived)…

Algebraic Geometry · Mathematics 2021-10-18 Nero Budur , Botong Wang

We give algebraic equivalents for certain desirable properties of pullback functors on categories of coverings and group sets, namely nullity zero, essential injectivity, and essential surjectivity. Nullity zero turns out to be equivalent…

Algebraic Topology · Mathematics 2012-05-15 Jack S. Calcut , John D. McCarthy , Jeremy J. Walthers

We study two classes of morphisms in infinite type: tamely presented morphisms and morphisms with coherent pullback. These are generalizations of finitely presented morphisms and morphisms of finite Tor-dimension, respectively. The class of…

Algebraic Geometry · Mathematics 2024-01-11 Sabin Cautis , Harold Williams

Let \(E\) be a finite-dimensional real vector space. We study invertible objects in the monoidal category of constructible sheaves on \(E\), endowed with the convolution product \(\star\). We show that the inverse of an invertible…

Algebraic Geometry · Mathematics 2026-04-30 Mehdi Benchoufi

We show the existence of semiorthogonal decompositions of Donaldson-Thomas categories for $(-1)$-shifted cotangent derived stacks associated with $\Theta$-stratifications on them. Our main result gives an analogue of window theorem for…

Algebraic Geometry · Mathematics 2021-06-11 Yukinobu Toda

The characteristic cycle of a complex of sheaves on a complex analytic space provides weak information about the complex; essentially, it yields the Euler characteristics of the hypercohomology of normal data to strata. We show how perverse…

Algebraic Geometry · Mathematics 2007-05-23 David B. Massey

This work studies conditions under which integral transforms induce exact functors on singularity categories between schemes that are proper over a Noetherian base scheme. A complete characterization for this behavior is provided, which…

Algebraic Geometry · Mathematics 2025-09-16 Uttaran Dutta , Pat Lank , Kabeer Manali Rahul

We introduce a class of perverse sheaves on a partial flag manifold of a connected reductive group G defined over a finite field which are equivariant under the action of the group of rational points of G. The definition of this class is…

Representation Theory · Mathematics 2007-05-23 G. Lusztig

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

Algebraic Geometry · Mathematics 2019-12-19 Shenghao Sun

We study the arithmetic Fourier transforms of trace functions on general connected commutative algebraic groups. To do so, we first prove a generic vanishing theorem for twists of perverse sheaves by characters, and using this tool, we…

Number Theory · Mathematics 2025-09-09 Arthur Forey , Javier Fresán , Emmanuel Kowalski

The purpose of these lectures is to introduce the notion of a Stokes-perverse sheaf as a receptacle for the Riemann-Hilbert correspondence for holonomic D-modules. They develop the original idea of P. Deligne in dimension one, and make it…

Algebraic Geometry · Mathematics 2012-11-02 Claude Sabbah

Let X be an algebraic variety with an action of an algebraic group G. Suppose X has a full exceptional collection of sheaves, and these sheaves are invariant under the action of the group. We construct a semiorthogonal decomposition of…

Algebraic Geometry · Mathematics 2015-05-13 Alexei Elagin

We prove that the bounded derived category of coherent sheaves with proper support is equivalent to the category of locally-finite, cohomological functors on the perfect derived category of a quasi-projective scheme over a field. We…

Algebraic Geometry · Mathematics 2011-05-18 Matthew Robert Ballard

In this paper we develop the theory of perverse sheaves on Artin stacks continuing the study in "The six operations for sheaves on Artin stacks I: Finite Coefficients" and "The six operations for sheaves on Artin stacks II: Adic…

Algebraic Geometry · Mathematics 2007-05-23 Yves Laszlo , Martin Olsson

The reverse derivative is a fundamental operation in machine learning and automatic differentiation. This paper gives a direct axiomatization of a category with a reverse derivative operation, in a similar style to that given by Cartesian…

Logic in Computer Science · Computer Science 2019-10-17 Robin Cockett , Geoffrey Cruttwell , Jonathan Gallagher , Jean-Simon Pacaud Lemay , Benjamin MacAdam , Gordon Plotkin , Dorette Pronk

We show how natural functors from the category of coherent sheaves on a projective scheme to categories of Kronecker modules can be used to construct moduli spaces of semistable sheaves. This construction simplifies or clarifies technical…

Algebraic Geometry · Mathematics 2009-11-11 Luis Álvarez-Cónsul , Alastair King