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A note on certain Tannakian group schemes

Sanjay Amrutiya (2020)

Archivum Mathematicum

In this note, we prove that the F -fundamental group scheme is a birational invariant for smooth projective varieties. We prove that the F -fundamental group scheme is naturally a quotient of the Nori fundamental group scheme. For elliptic curves, it turns out that the F -fundamental group scheme and the Nori fundamental group scheme coincide. We also consider an extension of the Nori fundamental group scheme in positive characteristic using semi-essentially finite vector bundles, and prove that in...

About G -bundles over elliptic curves

Yves Laszlo (1998)

Annales de l'institut Fourier

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 ) Z X ] / W . By a result of Looijenga, this shows that M G ( X ) is a weighted projective space.

ACM bundles on general hypersurfaces in P5 of low degree.

Luca Chiantini, Carlo K. Madonna (2005)

Collectanea Mathematica

In this paper we show that on a general hypersurface of degree r = 3,4,5,6 in P5 a rank 2 vector bundle ε splits if and only if h1ε(n) = h2ε(n) = 0 for all n ∈ Z. Similar results for r = 1,2 were obtained in [15], [16] and [2].

ACM bundles, quintic threefolds and counting problems

N. Mohan Kumar, Aroor Rao (2012)

Open Mathematics

We review some facts about rank two arithmetically Cohen-Macaulay bundles on quintic threefolds. In particular, we separate them into seventeen natural classes, only fourteen of which can appear on a general quintic. We discuss some enumerative problems arising from these.

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