Displaying similar documents to “About G -bundles over elliptic curves”

A criterion for virtual global generation

Indranil Biswas, A. J. Parameswaran (2006)

Annali della Scuola Normale Superiore di Pisa - Classe di Scienze

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Let X be a smooth projective curve defined over an algebraically closed field k , and let F X denote the absolute Frobenius morphism of X when the characteristic of k is positive. A vector bundle over X is called virtually globally generated if its pull back, by some finite morphism to X from some smooth projective curve, is generated by its global sections. We prove the following. If the characteristic of k is positive, a vector bundle E over X is virtually globally generated if and only...

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 .

Trivial noncommutative principal torus bundles

Stefan Wagner (2011)

Banach Center Publications

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A (smooth) dynamical system with transformation group ⁿ is a triple (A,ⁿ,α), consisting of a unital locally convex algebra A, the n-torus ⁿ and a group homomorphism α: ⁿ → Aut(A), which induces a (smooth) continuous action of ⁿ on A. In this paper we present a new, geometrically oriented approach to the noncommutative geometry of trivial principal ⁿ-bundles based on such dynamical systems, i.e., we call a dynamical system (A,ⁿ,α) a trivial noncommutative principal ⁿ-bundle if each isotypic...

Product preserving gauge bundle functors on vector bundles

Włodzimierz M. Mikulski (2001)

Colloquium Mathematicae

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A complete description is given of all product preserving gauge bundle functors F on vector bundles in terms of pairs (A,V) consisting of a Weil algebra A and an A-module V with d i m ( V ) < . Some applications of this result are presented.

Bounds for Chern classes of semistable vector bundles on complex projective spaces

Wiera Dobrowolska (1993)

Colloquium Mathematicae

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This work concerns bounds for Chern classes of holomorphic semistable and stable vector bundles on n . Non-negative polynomials in Chern classes are constructed for 4-vector bundles on 4 and a generalization of the presented method to r-bundles on n is given. At the end of this paper the construction of bundles from complete intersection is introduced to see how rough the estimates we obtain are.