Searcharxiv⌕ Search

arXiv subjects

L. Barbieri-Viale

Publications and source records attributed to L. Barbieri-Viale.

26 records · Page 2Linked to original sources
arXiv2005

Formal Hodge Theory

Formal (mixed) Hodge structures FHS are introduced in such a way that the Hodge realization of Deligne's 1-motives extends to a realization from Laumon's 1-motives to formal Hodge structures of level 1, providing an equivalence of categories. For the sake of exposition we here confine our study to level 1 mixed Hodge structures. However, it is conceivable and suitable to consider formal mixed Hodge structures with arbitrary Hodge numbers: generalizing our definition herebelow it's not that difficult and we will treat such a matter nextly.

math.AG↗
arXiv2005

On algebraic mixed Hodge substructures of H^2

This paper has been superseded to a great extent by the following: Paper: math.AG/0511558 Title: The Neron-Severi group of a proper seminormal complex variety Authors: L. Barbieri-Viale, A. Rosenschon & V. Srinivas Paper: math.AG/0102150 Title: Deligne's Conjecture on 1-Motives Authors: Luca Barbieri-Viale, Andreas Rosenschon, Morihiko Saito Journal-ref: Ann. of Math. (2), Vol. 158 (2003), no. 2, 593--633

math.AG↗
arXiv2001

On algebraic 1-motives related to Hodge cycles

The goal of this paper is to introduce Hodge 1-motives of algebraic varieties and to state a corresponding cohomological Grothendieck-Hodge conjecture, generalizing the classical Hodge conjecture to arbitrarily singular proper schemes.

math.AG↗
arXiv1999

Albanese and Picard 1-motives

We describe algebraically defined cohomological and homological Albanese and Picard 1-motives (or mixed motives) of any algebraic variety in characteristic zero, generalizing the classical Albanese and Picard varieties. We compute Hodge, l-adic and De Rham realizations proving Deligne's conjecture for the concerned mixed Hodge structures. We investigate functoriality, universality, homotopical invariance and invariance under formation of projective bundles. We compare our cohomological and homological 1-motives for normal schemes. For proper schemes, we obtain an Abel-Jacobi map from the (Levine-Weibel) Chow group of zero cycles to our cohomological Albanese 1-motive which is the universal regular homomorphism to semi-abelian varieties. By using this universal property we get 'motivic' Gysin maps for projective local complete intersection morphisms. This paper is an extended version of our preliminary Comptes Rendus Note, Academie des Sciences, Paris, Vol. 326, 1998.

math.AG↗
arXiv1996

Balanced Varieties

After the work of Bloch and Srinivas on correspondences and algebraic cycles we begin the study of a birational class of algebraic varieties determined by the property that a multiple of the diagonal is rationally equivalent to a cycle supported on proper subschemes.

alg-geom↗
arXiv1995

Roitman's theorem for singular complex projective surfaces

Let $X$ be a complex projective surface with arbitrary singularities. We construct a generalized Abel--Jacobi map $A_0(X)\to J^2(X)$ and show that it is an isomorphism on torsion subgroups. Here $A_0(X)$ is the appropriate Chow group of smooth 0-cycles of degree 0 on $X$, and $J^2(X)$ is the intermediate Jacobian associated with the mixed Hodge structure on $H^3(X)$. Our result generalizes a theorem of Roitman for smooth surfaces: if $X$ is smooth then the torsion in the usual Chow group $A_0(X)$ is isomorphic to the torsion in the usual Albanese variety $J^2(X)\cong Alb(X)$ by the classical Abel-Jacobi map.

alg-geom↗
arXiv1995

Bloch's conjecture revisited

Let $X$ be a non-singular projective complex surface. We can show that Bloch's conjecture (i.e., that if $p_g=0$ then the Albanese kernel vanishes) is equivalent to the following statement: If $p_g(X)=0$ then for any given Zariski open $U\subset X$ and $ω\in H^2(U,{\bf C})$ there is a smaller Zariski open $V\subset U$ such that $$ω\mid_V =ω'+ζ$$ where $ω'\in F^2H^2(V,{\bf C})$ and $ζ$ is integral.

alg-geom↗