English

Finite determinacy and approximation of flat maps

Commutative Algebra 2021-11-16 v2 Algebraic Geometry

Abstract

This paper considers the problems of finite determinacy and approximation of flat analytic maps from germs of real or complex analytic spaces. It is shown that the flatness of analytic maps from germs of real or complex analytic spaces whose local rings are Cohen-Macaulay is finitely determined. Further, it is shown that flat maps from complete intersection and Cohen-Macaulay analytic germs can be arbitrarily closely approximated by algebraic and Nash maps respectively in such a way that the Hilbert-Samuel function of the special fibre is preserved. It is also proved that in the complex case the preservation of the Hilbert-Samuel function implies the preservation of Whitney's tangent cone.

Keywords

Cite

@article{arxiv.2109.06821,
  title  = {Finite determinacy and approximation of flat maps},
  author = {Aftab Patel},
  journal= {arXiv preprint arXiv:2109.06821},
  year   = {2021}
}

Comments

13 pages. Substantial improvements in writing, existing theorems strengthened, several results added. arXiv admin note: text overlap with arXiv:1910.11498

R2 v1 2026-06-24T05:57:43.609Z