Journal ArticleDOI
Monodromy group for a strongly semistable principal bundle over a curve
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TLDR
In this paper, an affine group scheme X defined over the field k as well as a principal X-bundle S1755069607000151inline1 over the curve X is given by a xs0211A-graded neutral Tannakian category built out of all strongly semistable vector bundles over X.Abstract:
Let X be a geometrically irreducible smooth projective curve defined over a field k. Assume that X has a k-rational point; fix a k-rational point x e X. From these data we construct an affine group scheme X defined over the field k as well as a principal X-bundle S1755069607000151inline1 over the curve X. The group scheme X is given by a xs0211A-graded neutral Tannakian category built out of all strongly semistable vector bundles over X. The principal bundle S1755069607000151inline1 is tautological. Let G be a linear algebraic group, defined over k, that does not admit any nontrivial character which is trivial on the connected component, containing the identity element, of the reduced center of G. Let E G be a strongly semistable principal G-bundle over X. We associate to E G a group scheme M defined over k, which we call the monodromy group scheme of E G , and a principal M-bundle E M over X, which we call the monodromy bundle of E G . The group scheme M is canonically a quotient of X, and E M is the extension of structure group of S1755069607000151inline1. The group scheme M is also canonically embedded in the fiber Ad(E G ) x over x of the adjoint bundle.read more
Citations
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Journal ArticleDOI
Brauer obstruction for a universal vector bundle
TL;DR: BalBalaji et al. as mentioned in this paper proved that the Brauer group is Z / n Z, where n = g.c.d., and that Br (M ) is generated by the class of the projective bundle over M of relative dimension r − 1.
Journal ArticleDOI
On the s-fundamental group scheme. ii
TL;DR: In this paper, the authors used determinant line bundles to prove that the S-fundamental group of a product of two complete varieties of the Tannaka category of numerically flat vector bundles is the product of their fundamental groups as conjectured by Mehta and the author.
Book ChapterDOI
Vector bundles trivialized by proper morphisms and the fundamental group scheme
TL;DR: In this paper, it was shown that the Tannakian category associated to the vector bundles E on X such that f ∗ E is trivial is equivalent to the category of representations of a finite and etale group scheme.
Journal ArticleDOI
On the S-fundamental group scheme
TL;DR: In this paper, a new fundamental group scheme for varieties defined over an algebraically closed field of positive characteristic was introduced and used for generalization of some of C. Simpson's results to positive characteristic.
Journal ArticleDOI
Strongly semistable bundles on a curve over a finite field
TL;DR: In this paper, it was shown that a principal G-bundle on a smooth projective curve over a finite field is strongly semistable if and only if it is defined by a representation of the fundamental group scheme of the curve into G.
References
More filters
Book
Representations of algebraic groups
TL;DR: In this article, the Steinberg modules are used to represent the Frobenius kernels of finite algebraic groups and reduce them to reduction mod $p$ by using a simple reductive group.
Journal ArticleDOI
The irreducibility of the space of curves of given genus
Pierre Deligne,David Mumford +1 more
TL;DR: In this article, the authors implique l'accord avec les conditions generales d'utilisation (http://www.numdam.org/legal.php).
Journal ArticleDOI
Higgs bundles and local systems
TL;DR: In this paper, the authors implique l'accord avec les conditions générales d'utilisation (http://www.numdam.org/legal.php).
Journal ArticleDOI
Stable and unitary vector bundles on a compact Riemann surface
M. S. Narasimhan,C. S. Seshadri +1 more
TL;DR: In this article, it was shown that on the space of isomorphic classes of unitary vector bundles on X of a given rank, there is a natural structure of a normal projective variety (Theorem 8.1).
Journal ArticleDOI
Toward a numerical theory of ampleness
TL;DR: In this paper, the authors present a survey of vanishing theorems and related results of intersection numbers, including the polynomial theorem of Snapper and the ample cone of proper morphisms.