Displaying similar documents to “Theta characteristics of an algebraic curve”

Vector bundles on manifolds without divisors and a theorem on deformations

Georges Elencwajg, O. Forster (1982)

Annales de l'institut Fourier

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We study holomorphic vector bundles on non-algebraic compact manifolds, especially on tori. We exhibit phenomena which cannot occur in the algebraic case, e.g. the existence of 2-bundles that cannot be obtained as extensions of a sheaf of ideals by a line bundle. We prove some general theorems in deformations theory of bundles, which is our main tool.

Remarks on Seshadri constants of vector bundles

Christopher Hacon (2000)

Annales de l'institut Fourier

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We give a lower bound for the Seshadri constants of ample vector bundles which depends only on the numerical properties of the Chern classes and on a “stability” condition.

Poincaré bundles for projective surfaces

Nicole Mestrano (1985)

Annales de l'institut Fourier

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Let X be a smooth projective surface, K the canonical divisor, H a very ample divisor and M H ( c 1 , c 2 ) the moduli space of rank-two vector bundles, H -stable with Chern classes c 1 and c 2 . We prove that, if there exists c 1 ' such that c 1 is numerically equivalent to 2 c 1 ' and if c 2 - 1 4 c 1 2 is even, greater or equal to H 2 + H K + 4 , then there is no Poincaré bundle on M H ( c 1 , c 2 ) × X . Conversely, if there exists c 1 ' such that the number c 1 ' · c 1 is odd or if 1 2 c 1 2 - 1 2 c 1 · K - c 2 is odd, then there exists a Poincaré bundle on M H ( c 1 , c 2 ) × X .