Cohomology of a general instanton bundle
We show that the cohomology table of any coherent sheaf on projective space is a convergent—but possibly infinite—sum of positive real multiples of the cohomology tables of what we call supernatural sheaves.
We compute the unique nonzero cohomology group of a generic - linearized locally free -module, where is the identity component of a complex classical Lie supergroup and is an arbitrary parabolic subsupergroup. In particular we prove that for this cohomology group is an irreducible -module. As an application we generalize the character formula of typical irreducible -modules to a natural class of atypical modules arising in this way.
Let be a prime and let be a -group of matrices in , for some integer . In this paper we show that, when , a certain subgroup of the cohomology group is trivial. We also show that this statement can be false when . Together with a result of Dvornicich and Zannier (see [2]), we obtain that any algebraic torus of dimension enjoys a local-global principle on divisibility by .
Let 𝓐₂(n) = Γ₂(n)∖𝔖₂ be the quotient of Siegel's space of degree 2 by the principal congruence subgroup of level n in Sp(4,ℤ). This is the moduli space of principally polarized abelian surfaces with a level n structure. Let 𝓐₂(n)* denote the Igusa compactification of this space, and ∂𝓐₂(n)* = 𝓐₂(n)* - 𝓐₂(n) its "boundary". This is a divisor with normal crossings. The main result of this paper is the determination of H(∂𝓐₂(n)*) as a module over the finite group Γ₂(1)/Γ₂(n). As an application...
2000 Mathematics Subject Classification: Primary 14E15; Secondary 14C05,14L30.In this note we attempt to generalize a few statements drawn from the 3-dimensional McKay correspondence to the case of a cyclic group not in SL(3, C). We construct a smooth, discrepant resolution of the cyclic, terminal quotient singularity of type 1/r(1,1,r−1), which turns out to be isomorphic to Nakamura’s G-Hilbert scheme. Moreover we explicitly describe tautological bundles and use them to construct a dual basis to...