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If X is a complex projective variety with klt singularities, then the mixed Hodge structures on the first two singular cohomology groups are pure. We describe the pieces of the Hodge decomposition in terms of reflexive differential forms.…

Algebraic Geometry · Mathematics 2016-12-07 Martin Schwald

In this short paper, we give a $p$-adic analogue of the Hard Leftschetz Theorem.

Algebraic Geometry · Mathematics 2015-01-30 Daniel Caro

We give a short and self-contained proof of the Decomposition Theorem for the non-small resolution of a Special Schubert variety. We also provide an explicit description of the perverse cohomology sheaves. As a by-product of our approach,…

Algebraic Geometry · Mathematics 2019-10-28 Davide Franco

Motivated by definitions in mixed Hodge theory, we define the weight filtration and the monodromy weight filtration on the combinatorial intersection cohomology of a fan. These filtrations give a natural definition of the multivariable…

Combinatorics · Mathematics 2022-05-10 Ling Hei Tsang

We formulate a combinatorial version of the Intersection Hodge Conjecture for projective toric varieties. The conjecture asserts that the subspace of rational Hodge classes in the intersection cohomology $IH^*(X_\Sigma)$ is generated by the…

Algebraic Geometry · Mathematics 2025-12-09 Rizwan Jahangir

We construct real polarizable Hodge structures on the reduced leafwise cohomology of K\"ahler-Riemann foliations by complex manifolds. As in the classical case one obtains a hard Lefschetz theorem for this cohomology. Serre's K\"ahlerian…

Differential Geometry · Mathematics 2007-05-23 Christopher Deninger , Wilhelm Singhof

Inspired by the theory of hyperbolic polynomials and Hodge theory, we develop the theory of Lorentzian polynomials on cones. This notion captures the Hodge-Riemann relations of degree zero and one. Motivated by fundamental properties of…

Combinatorics · Mathematics 2025-12-10 Petter Brändén , Jonathan Leake

For a given flag variety, we characterize the primes $p$ for which there exists a weight $\lambda$ such that the Hard Lefschetz Theorem holds for multiplication by $\lambda$ on the cohomology of the flag variety with coefficients in an…

Representation Theory · Mathematics 2021-09-29 Leonardo Patimo

We prove the local hard Lefschetz theorem and local Hodge-Riemann bilinear relations for Soergel bimodules. Using results of Soergel and K\"ubel one may deduce an algebraic proof of the Jantzen conjectures. We observe that the Jantzen…

Representation Theory · Mathematics 2016-09-15 Geordie Williamson

Let $X$ be a $d$ dimensional projective manifold, $E$ be an ample vector bundle on $X$ and $0\le \lambda_N\le \lambda_{N-1} \le \cdots \le \lambda_1 \le \operatorname{rank}(E)$ be a partition of $d-2$. We prove that the Schur class…

Algebraic Geometry · Mathematics 2021-01-11 Julius Ross , Matei Toma

Since the 1974 paper by Peskine and Szpiro, liaison theory via complete intersections, and more generally via Gorenstein varieties, has become a standard tool kit in commutative algebra and algebraic geometry, allowing to compare algebraic…

Commutative Algebra · Mathematics 2024-12-18 Matteo Varbaro , Hongmiao Yu

We study the transversal hard Lefschetz theorem on a transversely symplectic foliation. This article extends the results of transversally symplectic flows (H.K.~Pak, "Transversal harmonic theory for transversally symplectic flows", J. Aust.…

Differential Geometry · Mathematics 2020-01-15 Jesús A. Álvarez López , Seoung Dal Jung

The algebra of smooth translation-invariant valuations on convex bodies, introduced by S.Alesker in the early 2000s, was in part proved and in part conjectured to satisfy properties formally analogous to those of the cohomology ring of a…

Differential Geometry · Mathematics 2024-02-15 Andreas Bernig , Jan Kotrbatý , Thomas Wannerer

We prove a version of the Lefschetz hyperplane theorem for fppf cohomology with coefficients in any finite commutative group scheme over the ground field. As consequences, we establish new Lefschetz results for the Picard scheme.

Algebraic Geometry · Mathematics 2024-11-20 Sean Cotner , Bogdan Zavyalov

This paper develops aspects of cosheaf theory on rigid analytic spaces, and demonstrates a sheaf-cosheaf Verdier duality equivalence theorem for overconvergent sheaves on separated, paracompact spaces, analogous to Jacob Lurie's treatment…

Algebraic Geometry · Mathematics 2020-11-25 Vaibhav Murali

The Alesker product turns the space of smooth translation-invariant valuations on convex bodies into a commutative associative unital algebra, satisfying Poincar\'e duality and the hard Lefschetz theorem. In this article, a version of the…

Metric Geometry · Mathematics 2021-08-10 Jan Kotrbatý

This article studies the relationship between tropical Severi varieties and secondary fans. In the case when tropical Severi varieties are hypersurfaces this relationship is very well known; specifically, in this case, a tropical Severi…

Algebraic Geometry · Mathematics 2015-12-08 Jihyeon Jessie Yang

The perverse filtration in cohomology and in cohomology with compact supports is interpreted in terms of kernels of restrictions maps to suitable subvarieties by using the Lefschetz hyperplane theorem and spectral objects. Various…

Algebraic Geometry · Mathematics 2010-06-15 Mark Andrea A. de Cataldo

The paper presents a proof of the Hodge Riemann relations for the combinatorial intersection cohomology of a polytope, as fist given by K.Karu, in terms of geometric operations on polytopes.

Algebraic Geometry · Mathematics 2007-05-23 G. Barthel , J. -P-Brasselet , K. -H. Fieseler , L. Kaup

The theorem of Barth-Lefschetz is a statement about the cohomology of a submanifold X of some projective space, in a range depending on the codimension of the embedding. Here this is generalized to the case of a submanifold X of a smooth…

Algebraic Geometry · Mathematics 2007-05-23 Joerg Zintl