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Minimal sections of conic bundles

Atanas Iliev (1999)

Bollettino dell'Unione Matematica Italiana

Sia p : X P 2 un fibrato in coniche standard con curva discriminante Δ di grado d . La varietà delle sezioni minime delle superfici p - 1 C , dove C è una curva di grado d - 3 , si spezza in due componenti C + e C - . Si prova che, mediante la mappa di Abel-Jacobi Φ , una di queste componenti domina la Jacobiana intermedia J X , mentre l'altra domina il divisore theta Θ J X . Questi risultati vengono applicati ad alcuni threefold di Fano birazionalmente equivalenti a un fibrato in coniche. In particolare si prova che il generico...

Mixed Hodge structure of affine hypersurfaces

Hossein Movasati (2007)

Annales de l’institut Fourier

In this article we give an algorithm which produces a basis of the n -th de Rham cohomology of the affine smooth hypersurface f - 1 ( t ) compatible with the mixed Hodge structure, where f is a polynomial in n + 1 variables and satisfies a certain regularity condition at infinity (and hence has isolated singularities). As an application we show that the notion of a Hodge cycle in regular fibers of f is given in terms of the vanishing of integrals of certain polynomial n -forms in n + 1 over topological n -cycles on...

Monodromy of a family of hypersurfaces

Vincenzo Di Gennaro, Davide Franco (2009)

Annales scientifiques de l'École Normale Supérieure

Let Y be an ( m + 1 ) -dimensional irreducible smooth complex projective variety embedded in a projective space. Let Z be a closed subscheme of Y , and δ be a positive integer such that Z , Y ( δ ) is generated by global sections. Fix an integer d δ + 1 , and assume the general divisor X | H 0 ( Y , Z , Y ( d ) ) | is smooth. Denote by H m ( X ; ) Z van the quotient of H m ( X ; ) by the cohomology of Y and also by the cycle classes of the irreducible components of dimension m of Z . In the present paper we prove that the monodromy representation on H m ( X ; ) Z van for the family of smooth...

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