English

On an extension of Galligo's theorem concerning the Borel-fixed points on the Hilbert scheme

Commutative Algebra 2007-05-23 v1 Algebraic Geometry

Abstract

Given an ideal II and a weight vector ww which partially orders monomials we can consider the initial ideal \initw(I)\init_w (I) which has the same Hilbert function. A well known construction carries this out via a one-parameter subgroup of a \GLn+1\GL_{n+1} which can then be viewed as a curve on the corresponding Hilbert scheme. Galligo \cite{galligo} proved that if II is in generic coordinates, and if ww induces a monomial order up to a large enough degree, then \initw(I)\init_w(I) is fixed by the action of the Borel subgroup of upper-triangular matrices. We prove that the direction the path approaches this Borel-fixed point on the Hilbert scheme is also Borel-fixed.

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Cite

@article{arxiv.math/0512023,
  title  = {On an extension of Galligo's theorem concerning the Borel-fixed points on the Hilbert scheme},
  author = {Morgan Sherman},
  journal= {arXiv preprint arXiv:math/0512023},
  year   = {2007}
}

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22 pages