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We develop a generalization to non-Witt spaces of the intersection homology theory of Goresky-MacPherson. The second author has described the self-dual sheaves compatible with intersection homology, and the other authors have described a…

Geometric Topology · Mathematics 2013-08-20 Pierre Albin , Markus Banagl , Eric Leichtnam , Rafe Mazzeo , Paolo Piazza

We present a functorial computation of the equivariant intersection cohomology of a hypertoric variety, and endow it with a natural ring structure. When the hyperplane arrangement associated with the hypertoric variety is unimodular, we…

Algebraic Geometry · Mathematics 2015-05-13 Tom Braden , Nicholas J. Proudfoot

We discuss the relationship between kernels, images and cokernels of morphisms between perverse sheaves and induced maps on stalk cohomology.

Algebraic Geometry · Mathematics 2016-02-25 David B. Massey

We relate shuffle algebras, as defined by Nichols, Feigin-Odesskii and Rosso, to perverse sheaves on symmetric products of the complex line (i.e., on the spaces of monic polynomials stratified by multiplicities of roots). More precisely, we…

Algebraic Topology · Mathematics 2020-01-14 Mikhail Kapranov , Vadim Schechtman

We derive a formula for the Milnor class of scheme-theoretic global complete intersections (with arbitrary singularities) in a smooth variety in terms of the Segre class of its singular scheme. In codimension one the formula recovers a…

Algebraic Geometry · Mathematics 2013-11-19 James Fullwood

In previous works, we have introduced the blown-up intersection cohomology and used it to extend Sullivan's minimal models theory to the framework of pseudomanifolds, and to give a positive answer to a conjecture of M. Goresky and W. Pardon…

Algebraic Topology · Mathematics 2018-06-20 David Chataur , Martintxo Saralegi-Aranguren , Daniel Tanré

We show that intersection homology extends Poincare duality to manifold homotopically stratified spaces (satisfying mild restrictions). This includes showing that, on such spaces, the sheaf of singular intersection chains is…

Geometric Topology · Mathematics 2011-03-31 Greg Friedman

In a series of papers the authors introduced the so-called blown-up intersection cochains. These cochains are suitable to study products and cohomology operations of intersection cohomology of stratified spaces. The aim of this paper is to…

Algebraic Topology · Mathematics 2020-09-22 David Chataur , Martintxo Saralegi-Aranguren , Daniel Tanré

We investigate the relation between codimension two smooth complete intersections in a projective space and some naturally associated graded algebras. We give some examples of log-concave polynomials and we propose two conjectures for these…

Algebraic Geometry · Mathematics 2014-01-15 Gabriel Sticlaru

We consider a hypersurface in $\mathbb{C}^n$ with an isolated singular point at the origin, and study the mixed Hodge structure of the stalk of its intersection cohomology complex at the origin. In particular we express the dimension of…

Algebraic Geometry · Mathematics 2017-02-13 Takahiro Saito

Suppose that $f$ defines a singular, complex affine hypersurface. If the critical locus of $f$ is one-dimensional, we obtain new general bounds on the ranks of the homology groups of the Milnor fiber of $f$. This result has an interesting…

Algebraic Geometry · Mathematics 2007-05-23 Lê Dũng Tráng , David B. Massey

Intersection cohomology is a way to enhance classical cohomology, allowing us to use a famous result called Poincar\'e duality on a large class of spaces known as stratified pseudomanifolds. There is a theoretically powerful way to arrive…

Algebraic Topology · Mathematics 2022-12-08 Sebastian Cea

We study intersection cohomology of character varieties for punctured Riemann surfaces with prescribed monodromies around the punctures. Relying on previous result from Mellit for semisimple monodromies we compute the intersection…

Algebraic Geometry · Mathematics 2022-02-14 Mathieu Ballandras

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

Let $\A$ be an arrangement of affine lines in $\C^2,$ with complement $\M(\A).$ The (co)homo-logy of $\M(\A)$ with twisted coefficients is strictly related to the cohomology of the Milnor fibre associated to the conified arrangement,…

Algebraic Topology · Mathematics 2017-03-09 M. Salvetti , M. Serventi

To a coarse structure we associate a Grothendieck topology which is determined by coarse covers. A coarse map between coarse spaces gives rise to a morphism of Grothendieck topologies. This way we define sheaves and sheaf cohomology on…

Algebraic Geometry · Mathematics 2022-03-24 Elisa Hartmann

We start with a discussion on Alexander invariants, and then prove some general results concerning the divisibility of the Alexander polynomials and the supports of the Alexander modules, via Artin's vanishing theorem for perverse sheaves.…

Algebraic Topology · Mathematics 2012-04-03 Alexandru Dimca , Laurentiu Maxim

There are several topological spaces associated to a complex hyperplane arrangement: the complement and its boundary manifold, as well as the Milnor fiber and its own boundary. All these spaces are related in various ways, primarily by a…

Algebraic Geometry · Mathematics 2014-10-14 Alexander I. Suciu

We investigate the cohomology of the Milnor fibre of a reflection arrangement as a module for the group $\Gamma$ generated by the reflections, together with the cyclic monodromy. Although we succeed completely only for unitary reflection…

Algebraic Geometry · Mathematics 2013-07-29 Alexandru Dimca , Gus Lehrer

For isolated complex hypersurface singularities with real defining equation we show the existence of a monodromy vector field such that complex conjugation intertwines the local monodromy diffeomorphism with its inverse. In particular, it…

Algebraic Geometry · Mathematics 2007-05-23 Norbert A'Campo