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Related papers: Lefschetz classes on projective varieties

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Let Y be a normal crossing divisor in the smooth projective algebraic variety X (defined over ${\mathbb C}$) and let U be a tubular neighbourhood of Y in X. We construct homological cycles generating $H_*(A,B)$, where (A,B) is one of the…

Algebraic Geometry · Mathematics 2007-05-23 Fouad Elzein , András Némethi

We introduce a general technique for decomposing monomial algebras which we use to study the Lefschetz properties. We apply our technique to various classes of algebras, including monomial almost complete intersections and Gorenstein…

Commutative Algebra · Mathematics 2021-11-30 Oleksandra Gasanova , Samuel Lundqvist , Lisa Nicklasson

We reproduce the quantum cohomology of toric varieties (and of some hypersurfaces in projective spaces) as the cohomology of certain vertex algebras with differential. The deformation technique allows us to compute the cohomology of the…

Algebraic Geometry · Mathematics 2007-05-23 F. Malikov , V. Schechtman

We introduce a homological Lefschetz conjecture on (rational) Chow groups, which can be deduced from some well known conjectures, and illustrate it by a series of key examples. We then prove the injectivity of the push-forward morphism on…

Algebraic Geometry · Mathematics 2021-03-31 Kalyan Banerjee , Jaya NN Iyer , James D. Lewis

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 construct a logarithmic model of connections on smooth quasi-projective $n$-dimensional geometrically irreducible varieties defined over an algebraically closed field of characteristic $0$. It consists of a good compactification of the…

Algebraic Geometry · Mathematics 2019-05-03 Hélène Esnault , Claude Sabbah

In order to understand the structure of the cohomologies involved in the study of projectively equivariant quantizations, we introduce a notion of affine representation of a Lie algebra.We show how it is related to linear representations…

Differential Geometry · Mathematics 2007-05-23 Sarah Hansoul , Pierre B. A. Lecomte

Let $X$ be a complex submanifold of dimension $d$ of $\mathbb P^m\times\mathbb P^n$ ($m\geq n\geq 2$) and denote by $\alpha\colon\Pic(\mathbb P^m\times\mathbb P^n)\to \Pic(X)$ the restriction map of Picard groups, by $N_{X|\mathbb…

Algebraic Geometry · Mathematics 2007-05-23 Lucian Badescu , Flavia Repetto

A rather simple natural outer derivation of the graded Lie algebra of all vector valued differential forms with the Fr\"olicher-Nijenhuis bracket turns out to be a differential and gives rise to a cohomology of the manifold, which is…

Differential Geometry · Mathematics 2016-09-06 Peter W. Michor , Hubert Schicketanz

We give a definition of differentiable cohomology of a Lie group G (possibly infinite-dimensional) with coefficients in any abelian Lie group. This differentiable cohomology maps both to the cohomology of the group made discrete and to Lie…

Differential Geometry · Mathematics 2007-05-23 Jean-Luc Brylinski

The main goal of the present paper is to generalize the results of~\cite{TroLNM,TroBoch} in the following way: To be able to define $K_0(A)\o\C$-valued Lefschetz numbers of the first type of an endomorphism $V$ on a C*-elliptic complex one…

funct-an · Mathematics 2025-05-08 Michael Frank , Evgenij V. Troitsky

We establish the Borel computability of various C$^*$-algebra invariants, including the Elliott invariant and the Cuntz semigroup. As applications we deduce that AF algebras are classifiable by countable structures, and that a conjecture of…

Operator Algebras · Mathematics 2015-03-13 Ilijas Farah , Andrew S. Toms , Asger Törnquist

In this article we describe the projective representation of Plesken Lie algebras and equivalent central extensions of these algebras. Further it is also shown that there exists a bijective correspondence between second cohomology group,…

Representation Theory · Mathematics 2022-11-17 P G Romeo , Arjun S N

In this paper, we prove that a smooth projective variety $X$ of characteristic $p>0$ is an ordinary abelian variety if and only if $K_X$ is pseudo-effective and $F^e_*\mathcal O_X$ splits into a direct sum of line bundles for an integer $e$…

Algebraic Geometry · Mathematics 2017-08-30 Sho Ejiri , Akiyoshi Sannai

We invent a new cohomology theory for Lie triple algebras. Using this cohomology, we introduce the notions of 2-term $L_\infty$-triple algebras and Lie triple 2-algebras. We prove that the category of 2-term $L_\infty$-triple algebras is…

Rings and Algebras · Mathematics 2023-10-23 Tao Zhang , Zhang-Ju Liu

We generalize the Frobenius-Schur theorem to $C^*$-categories. From this category-theoretical point of view, we introduce the notions of real, complex and quaternionic representations of Hopf $C^*$-algebras. Based on these definitions, we…

Representation Theory · Mathematics 2013-03-06 Kenichi Shimizu

We introduce regular morphisms of topological quivers and show that they give rise to a subcategory of the category of topological quivers and quiver morphisms. Our regularity conditions render the topological quiver C*-algebra construction…

Operator Algebras · Mathematics 2025-07-15 Mariusz Tobolski

We construct a cochain map embedding the cohomology complex of any dual Leibniz algebra $B$ into the Lie algebra cochain complex of $\mathfrak{g} \otimes B$, where $\mathfrak{g}$ is a Leibniz algebra. This reduces the study of dual Leibniz…

Rings and Algebras · Mathematics 2025-12-23 Hassan Alhussein

We prove a motivic version of the Lefschetz hyperplane theorem for a smooth ample divisor $\Theta$ on an Abelian variety. We use this to construct a motive $P$ that realizes the primitive cohomology of $\Theta$.

Algebraic Geometry · Mathematics 2016-03-15 Humberto A. Diaz

In this paper, we consider Leibniz algebras with derivations. A pair consisting of a Leibniz algebra and a distinguished derivation is called a LeibDer pair. We define a cohomology theory for LeibDer pair with coefficients in a…

Rings and Algebras · Mathematics 2020-03-19 Apurba Das
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