English

Canonical map of low codimensional subvarieties

Algebraic Geometry 2007-05-23 v1

Abstract

Fix integers a1a\geq 1, bb and cc. We prove that for certain projective varieties VPrV\subset{\bold P}^r (e.g. certain possibly singular complete intersections), there are only finitely many components of the Hilbert scheme parametrizing irreducible, smooth, projective, low codimensional subvarieties XX of VV such that h0(X,\CalOX(aKXbHX))λdϵ1+c(1h<ϵ2pg(X(h))), h^0(X,\Cal O_X(aK_X-bH_X)) \leq \lambda d^{\epsilon_1}+c(\sum_{1\leq h < \epsilon_2}p_g(X^{(h)})), where dd, KXK_X and HXH_X denote the degree, the canonical divisor and the general hyperplane section of XX, pg(X(h))p_g(X^{(h)}) denotes the geometric genus of the general linear section of XX of dimension hh, and where λ\lambda, ϵ1\epsilon_1 and ϵ2\epsilon_2 are suitable positive real numbers depending only on the dimension of XX, on aa and on the ambient variety VV. In particular, except for finitely many families of varieties, the canonical map of any irreducible, smooth, projective, low codimensional subvariety XX of VV, is birational.

Keywords

Cite

@article{arxiv.math/0403205,
  title  = {Canonical map of low codimensional subvarieties},
  author = {Valentina Beorchia and Ciro Ciliberto and Vincenzo Di Gennaro},
  journal= {arXiv preprint arXiv:math/0403205},
  year   = {2007}
}

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31 pages