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On a complex contact manifold, or complex symplectic manifold with weight-1 circle action, we construct a sheaf of stable categories carrying a t-structure which is locally equivalent to a microlocalization of the perverse t-structure.

Symplectic Geometry · Mathematics 2025-12-17 Laurent Côté , Christopher Kuo , David Nadler , Vivek Shende

It is usually not straightforward to work with the category of perverse sheaves on a variety using only its definition as a heart of a $t$-structure. In this paper, the category of perverse sheaves on a smooth toric variety with its orbit…

Algebraic Geometry · Mathematics 2024-12-30 Sergey Guminov

Perverse schobers are categorifications of perverse sheaves. We construct a perverse schober on a partial compactification of the stringy K\"ahler moduli space (SKMS) associated by Halpern-Leistner and Sam to a quasi-symmetric…

Algebraic Geometry · Mathematics 2019-09-06 Špela Špenko , Michel Van den Bergh

We describe an algorithm computing the monodromy and the pole order filtration on the top Milnor fiber cohomology of hypersurfaces in $\mathbb{P}^n$ whose pole order spectral sequence degenerates at the second page. In the case of…

Algebraic Geometry · Mathematics 2017-10-05 Alexandru Dimca , Gabriel Sticlaru

Microlocal perverse sheaves form a stack on the cotangent bundle of a complex manifold that is the analogue of the stack of perverse sheaves on the manifold itself. We give an embedding of the stack of microlocal perverse sheaves into a…

Algebraic Geometry · Mathematics 2007-05-23 S. Gelfand , R. MacPherson , K. Vilonen

This paper continues our researches \cite{DS1, DS2, DS3} by computing some invariants based on Hilbert-Poincar\'{e} series associated to Milnor algebras. Our computations are for some of the classical surfaces and 3-folds with different…

Algebraic Geometry · Mathematics 2013-10-01 Gabriel Sticlaru

Let H be an arrangement of real hyperplanes in R^n. The complexification of H defines a natural stratification of C^n. We denote by Perv(C^n, H) the category of perverse sheaves on C^n smooth with respect to this stratification. We give a…

Algebraic Topology · Mathematics 2015-02-04 Mikhail Kapranov , Vadim Schechtman

We explain how to compute simple perverse sheaves on the stack of $G$-zips and do these computations in several examples.

Algebraic Geometry · Mathematics 2025-05-16 Christopher Lang

We prove a criterion for determining whether the normalization of a complex analytic space on which the constant sheaf is perverse is a rational homology manifold, using a perverse sheaf known as the multiple-point complex. This perverse…

Algebraic Geometry · Mathematics 2018-08-13 Brian Hepler

This paper is an introduction to the use of perverse sheaves with positive characteristic coefficients in modular representation theory. In the first part, we survey results relating singularities in finite and affine Schubert varieties and…

Representation Theory · Mathematics 2014-10-07 Daniel Juteau , Carl Mautner , Geordie Williamson

We analyze irreducible perverse sheaves on abelian varieties, defined over the complex numbers or the algebraic closure of a finite field, whose Euler characteristic is zero. We give a description of such perverse sheaves under assumptions…

Algebraic Geometry · Mathematics 2015-10-27 Rainer Weissauer

The goal of this paper is to explain how basic properties of perverse sheaves sometimes translate via Riemann-Hilbert correspondences (in both characteristic $0$ and characteristic $p$) to highly non-trivial properties of singularities,…

Algebraic Geometry · Mathematics 2025-03-26 Bhargav Bhatt , Manuel Blickle , Gennady Lyubeznik , Anurag K. Singh , Wenliang Zhang

In this note, we consider perverse sheaves on the nilpotent cone. We prove orthogonality relations for the equivariant category of sheaves on the nilpotent cone in a method similar to Lusztig's for character sheaves. We also consider…

Representation Theory · Mathematics 2016-11-07 Laura Rider , Amber Russell

For a complex reductive Lie group G with Lie algebra g, Cartan subalgebra h and Weyl group W, we describe the category of perverse sheaves on h/W smooth w.r.t the natural stratification. The answer is given in terms of mixed Bruhat sheaves,…

Algebraic Topology · Mathematics 2021-12-14 Mikhail Kapranov , Vadim Schechtman

We study a class of perverse sheaves on the variety of pairs (P,gU_P) where P runs through a conjugacy class of parabolics in a connected reductive group G and gU_P runs through G/U_P. This is a generalization of the theory of character…

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

This is the first of two papers studying moduli spaces of a certain class of coherent sheaves, which we call {\it stable perverse coherent sheaves}, on the blowup of a projective surface. They are used to relate usual moduli spaces of…

Algebraic Geometry · Mathematics 2008-06-03 Hiraku Nakajima , Kota Yoshioka

It is known that the lens space $L(2n,1)$ supports a virtually overtwisted contact structure arising as the boundary of the Milnor fiber of a complex hypersurface singularity. In this article we study the problem of realizing other…

Geometric Topology · Mathematics 2019-08-05 Edoardo Fossati

We suggest a possibility for a categorical generalization of the concept of a perverse sheaf, in which vector spaces are replaced by triangulated categories. We call such hypothetical objects perverse Schobers and consider several examples,…

Algebraic Geometry · Mathematics 2015-11-19 Mikhail Kapranov , Vadim Schechtman

Quadric hypersurfaces are well-known to satisfy the Hasse principle. However, this is no longer true in the case of the Hasse principle for integral points, where counter-examples are known to exist in dimension 1 and 2. This work explores…

Number Theory · Mathematics 2025-11-25 Vladimir Mitankin

We conjecture that any perverse sheaf on a compact aspherical K\"ahler manifold has non-negative Euler characteristic. This extends the Singer-Hopf conjecture in the K\"ahler setting. We verify the stronger conjecture when the manifold X…

Algebraic Geometry · Mathematics 2025-01-31 Donu Arapura , Botong Wang