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Related papers: The weight filtration for real algebraic varieties

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We associate to each real algebraic variety a filtered chain complex, the weight complex, which is well-defined up to filtered quasi-isomorphism, and which induces on classical (compactly supported) homology with Z/2 coefficients an analog…

Algebraic Geometry · Mathematics 2017-01-16 Clint McCrory , Adam Parusinski

We show that the etale cohomology (with compact supports) of an algebraic variety $X$ over an algebraically closed field has the canonical weight filtration $W$, and prove that the middle weight part of the cohomology with compact supports…

Algebraic Geometry · Mathematics 2007-05-23 Masaki Hanamura , Morihiko Saito

We show that in the category of complex algebraic varieties, the Eilenberg--Moore spectral sequence can be endowed with a weight filtration. This implies that it degenerates if all involved spaces have pure cohomology. As application, we…

Algebraic Geometry · Mathematics 2007-05-23 Matthias Franz , Andrzej Weber

We associate to each algebraic variety defined over $\mathbb{R}$ a filtered cochain complex, which computes the cohomology with compact supports and $\mathbb{Z}\_2$-coefficients of the set of its real points. This filtered complex is…

Algebraic Geometry · Mathematics 2016-02-01 Thierry Limoges , Fabien Priziac

We first show the existence of a weight filtration on the equivariant cohomology of real algebraic varieties equipped with the action of a finite group, by applying group cohomology to the dual geometric filtration. We then prove the…

Algebraic Geometry · Mathematics 2017-08-18 Fabien Priziac

We show the existence of an equivariant weight filtration on the equivariant homology of real algebraic varieties equipped with a finite group action, by applying group homology onto the weight complex of McCrory and Parusi\'nski. The group…

Algebraic Geometry · Mathematics 2017-03-09 Fabien Priziac

We study the first step of the weight filtration on the cohomology of a proper complex algebraic variety, which we call the combinatorial part. We obtain a natural upper bound on its size, which gives rather strong information about the…

Algebraic Geometry · Mathematics 2009-02-26 Donu Arapura , Parsa Bakhtary , Jarosław Włodarczyk

Let G be a complex, connected, reductive algebraic group with Weyl group W and Steinberg variety Z. We show that the graded Borel-Moore homology of Z is isomorphic to the smash product of the coinvariant algebra of W and the group algebra…

Representation Theory · Mathematics 2009-07-31 J. Matthew Douglass , Gerhard Roehrle

We describe the weight filtration in the cohomology of toric varieties. We present a role of the Frobenius automorphism in an elementary way. We prove that equivariant intersection homology of an arbitrary toric variety is pure. We obtain…

Algebraic Geometry · Mathematics 2007-05-23 Andrzej Weber

In this paper, we extract natural invariants of a singularity by using the Deligne weight filtration on the cohomology of an exceptional fibre of a resolution, and also on the intersection cohomology of the link. Our primary goal is to…

Algebraic Geometry · Mathematics 2013-01-25 Donu Arapura , Parsa Bakhtary , Jarosław Włodarczyk

We give an alternative construction of Totaro's weight filtration on singular homology of the real points of a real algebraic variety. Our construction shows that this filtration comes from Bondarko's weight filtration on Voevodsky motives.

Algebraic Geometry · Mathematics 2025-12-01 Raphaël Ruimy

We extend Deligne's weight filtration to the integer cohomology of complex analytic spaces (endowed with an equivalence class of compactifications). In general, the weight filtration that we obtain is not part of a mixed Hodge structure.…

Algebraic Geometry · Mathematics 2014-09-30 Joana Cirici , Francisco Guillén

Let X be a smooth simplicial toric variety. Let Z be the set of T-fixed points of X. We construct a filtration for A(Z), the ring of complex-valued functions on Z, such that Gr A(Z) is isomorphic to the cohomology algebra of X. This is the…

Algebraic Geometry · Mathematics 2007-05-23 Kiumars Kaveh

We prove that there is a natural plectic weight filtration on the cohomology of Hilbert modular varieties in the spirit of Nekovar and Scholl. This is achieved with the help of Morel's work on weight t-structures and a detailed study of…

Number Theory · Mathematics 2021-07-06 Zhiyou Wu

We study the dual complexes of boundary divisors in log resolutions of compactifications of algebraic varieties and show that the homotopy types of these complexes are independent of all choices. Inspired by recent developments in…

Algebraic Geometry · Mathematics 2016-04-19 Sam Payne

We recall first some basic facts on weighted homogeneous functions and filtrations in the ring $A$ of formal power series. We introduce next their analogues for weighted homogeneous diffeomorphisms and vector fields. We show that the Milnor…

Algebraic Geometry · Mathematics 2019-04-09 Imran Ahmed

We prove an equivalence between filtrations of primitive bialgebras and filtrations of factorizable perverse sheaves, generalizing the results obtained by Kapranov-Schechtman. Under this equivalence, we find that the word length filtration…

Number Theory · Mathematics 2026-01-08 Zhao Yu Ma

There are several interesting filtrations on the Cartan subalgebra of a complex simple Lie algebra coming from very different contexts: one is the principal filtration coming from the Langlands dual, one is coming from the Clifford algebra…

Representation Theory · Mathematics 2020-01-20 Nilamsari Kusumastuti , Anne Moreau

Let $G$ be a connected reductive algebraic group. In this note we prove that for a quasi-affine $G$-spherical variety the weight monoid is determined by the weights of its non-trivial $\mathbb{G}_a$-actions that are homogeneous with respect…

Algebraic Geometry · Mathematics 2019-11-26 Andriy Regeta , Immanuel van Santen

Let $G/H$ be a homogeneous variety, and let $X$ be a $G$-equivariant embedding of $G/H$such that the number of $G$-orbits in $X$ is finite. We show that the equivariant Borel-Moore homology of $X$ has a filtration with associated graded…

Algebraic Geometry · Mathematics 2019-06-06 Aram Bingham , Mahir Bilen Can , Yıldıray Ozan
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