English

Taylor Polynomials of Rational Functions

Algebraic Geometry 2023-04-04 v1 Symbolic Computation Commutative Algebra

Abstract

A Taylor variety consists of all fixed order Taylor polynomials of rational functions, where the number of variables and degrees of numerators and denominators are fixed. In one variable, Taylor varieties are given by rank constraints on Hankel matrices. Inversion of the natural parametrization is known as Pad\'e approximation. We study the dimension and defining ideals of Taylor varieties. Taylor hypersurfaces are interesting for projective geometry, since their Hessians tend to vanish. In three and more variables, there exist defective Taylor varieties whose dimension is smaller than the number of parameters. We explain this with Fr\"oberg's Conjecture in commutative algebra.

Keywords

Cite

@article{arxiv.2304.00712,
  title  = {Taylor Polynomials of Rational Functions},
  author = {Aldo Conca and Simone Naldi and Giorgio Ottaviani and Bernd Sturmfels},
  journal= {arXiv preprint arXiv:2304.00712},
  year   = {2023}
}

Comments

20 pages

R2 v1 2026-06-28T09:45:47.102Z