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On the Hodge cycles of Prym varieties

Indranil Biswas (2004)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

We show that the Néron–Severi group of the Prym variety for a degree three unramified Galois covering of a hyperelliptic Riemann surface has a distinguished subgroup of rank three. For the general hyperelliptic curve, the algebra of Hodge cycles on the Prym variety is generated by this group of rank three.

On the structure of Brieskorn lattice

Morihiko Saito (1989)

Annales de l'institut Fourier

We study the structure of the filtered Gauss-Manin system associated to a holomorphic function with an isolated singularity, and get a basis of the Brieskorn lattice Ω X , 0 n + 1 / d f d Ω X , 0 n + 1 over { { t - 1 } } such that the action of t is expressed by t v = A 0 + A 1 t - 1 v for two matrices A 0 , A 1 with A 1 semi-simple, where v = t ( v 1 ... v μ ) is the basis. As an application, we calculate the b -function of f in the case of two variables.

On the weight filtration of the homology of algebraic varieties : the generalized Leray cycles

Fouad Elzein, András Némethi (2002)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

Let Y be a normal crossing divisor in the smooth complex projective algebraic variety X and let U be a tubular neighbourhood of Y in X . Using geometrical properties of different intersections of the irreducible components of Y , and of the embedding Y X , we provide the “normal forms” of a set of geometrical cycles which generate H * ( A , B ) , where ( A , B ) is one of the following pairs ( Y , ) , ( X , Y ) , ( X , X - Y ) , ( X - Y , ) and ( U , ) . The construction is compatible with the weights in H * ( A , B , ) of Deligne’s mixed Hodge structure. The main technical part...

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