English

Higher symmetric powers of tautological bundles on Hilbert schemes of points on a surface

Algebraic Geometry 2015-12-24 v2

Abstract

We study general symmetric powers SkL[n]S^k L^{[n]} of a tautological bundle L[n]L^{[n]} on the Hilbert scheme X[n]X^{[n]} of nn points over a smooth quasi-projective surface XX, associated to a line bundle LL on XX. Let VLV_L be the Sn\mathfrak{S}_n-vector bundle on XnX^n defined as the exterior direct sum LLL \boxplus \cdots \boxplus L. We prove that the Bridgeland-King-Reid transform Φ(SkL[n])\mathbf{\Phi}(S^k L^{[n]}) of symmetric powers SkL[n]S^k L^{[n]} is quasi isomorphic to the last term of a finite decreasing filtration on the natural vector bundle SkVLS^k V_L, defined by kernels of operators DLlD^l_L, which operate locally as higher order restrictions to pairwise diagonals. We use this description and the natural filtration on (SkVL)Sn(S^k V_L)^{\mathfrak{S}_n} induced by the decomposition in direct sum, to obtain, for n=2n =2 or k4k \leq 4, a finite decreasing filtration W\mathcal{W}^\bullet on the direct image μ(SkL[n])\mu_*(S^k L^{[n]}) for the Hilbert-Chow morphism whose graded sheaves we control completely. As a consequence of this structural result, we obtain a chain of cohomological consequences, like a spectral sequence abutting to the cohomology of symmetric powers SkL[n]S^k L^{[n]}, an effective vanishing theorem for the cohomology of symmetric powers SkL[n]DAS^k L^{[n]} \otimes \mathcal{D}_A twisted by the determinant, in presence of adequate positivity hypothesis on LL and AA, as well as universal formulas for their Euler-Poincar\'e characteristic.

Keywords

Cite

@article{arxiv.1502.07595,
  title  = {Higher symmetric powers of tautological bundles on Hilbert schemes of points on a surface},
  author = {Luca Scala},
  journal= {arXiv preprint arXiv:1502.07595},
  year   = {2015}
}

Comments

pdflatex, 70 pages