A criterion for virtual global generation

Indranil Biswas; A. J. Parameswaran

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Displaying similar documents to “A criterion for virtual global generation”

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 $c_{2} - \frac{1}{4} c_{1}^{2}$ is even, greater or equal to $H^{2} + H K + 4$ , then there is no Poincaré bundle on $M_{H} (c_{1}, c_{2}) \times X$ . Conversely, if there exists $c_{1}^{'}$ such that the number $c_{1}^{'} \cdot c_{1}$ is odd or if $\frac{1}{2} c_{1}^{2} - \frac{1}{2} c_{1} \cdot K - c_{2}$ is odd, then there exists a Poincaré bundle on $M_{H} (c_{1}, c_{2}) \times X$ .

About $G$ -bundles over elliptic curves

Yves Laszlo (1998)

Annales de l'institut Fourier

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Let $G$ be a complex algebraic group, simple and simply connected, $T$ a maximal torus and $W$ the Weyl group. One shows that the coarse moduli space $M_{G} (X)$ parametrizing $S$ -equivalence classes of semistable $G$ -bundles over an elliptic curve $X$ is isomorphic to $[Γ (T) \otimes_{Z} X] / W$ . By a result of Looijenga, this shows that $M_{G} (X)$ is a weighted projective space.

On generation of jets for vector bundles.

Mauro C. Beltrametti, Sandra Di Rocco, Andrew J. Sommese (1999)

Revista Matemática Complutense

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We introduce and study the k-jet ampleness and the k-jet spannedness for a vector bundle, E, on a projective manifold. We obtain different characterizations of projective space in terms of such positivity properties for E. We compare the 1-jet ampleness with different notions of very ampleness in the literature.

Natural affinors on the (r,s,q)-cotangent bundle of a fibered manifold

J. Kurek, W. M. Mikulski (2004)

Annales Polonici Mathematici

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For natural numbers r,s,q,m,n with s ≥ r ≤ q we describe all natural affinors on the (r,s,q)-cotangent bundle $T^{r, s, q *} Y$ over an (m,n)-dimensional fibered manifold Y.

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...

On the fiber product preserving gauge bundle functors on vector bundles

Włodzimierz M. Mikulski (2003)

Annales Polonici Mathematici

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We present a complete description of all fiber product preserving gauge bundle functors F on the category $_{m}$ of vector bundles with m-dimensional bases and vector bundle maps with local diffeomorphisms as base maps. Some corollaries of this result are presented.

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 $d i m_{ℝ} (V) < \infty$ . Some applications of this result are presented.

On quasijet bundles

Tomáš, Jiří

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In this paper a Weil approach to quasijets is discussed. For given manifolds $M$ and $N$ , a quasijet with source $x \in M$ and target $y \in N$ is a mapping $T_{x}^{r} M \to T_{y}^{r} N$ which is a vector homomorphism for each one of the $r$ vector bundle structures of the iterated tangent bundle $T^{r}$ [, Casopis Pest. Mat. 111, No. 4, 345-352 (1986; Zbl 0611.58004)]. Let us denote by $Q J^{r} (M, N)$ the bundle of quasijets from $M$ to $N$ ; the space ${\tilde{J}}^{r} (M, N)$ of non-holonomic $r$ -jets from $M$ to $N$ is embeded into $Q J^{r} (M, N)$ . On the other hand, the bundle $Q T_{m}^{r} N$ of $(m, r)$ -quasivelocities...

A footnote to a paper by Noma

Antonio Lanteri, Francesco Russo (1993)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

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Let $E$ be a globally generated ample vector bundle of rank $\geq 2$ on a complex projective smooth surface $X$ . By extending a recent result by A. Noma, we classify pairs $(X, E)$ as above satisfying $c_{2} (E) = 2$ .