English

On Rees algebras of ideals and modules with weak residual conditions

Commutative Algebra 2024-09-24 v1 Algebraic Geometry

Abstract

Let EE be a module of projective dimension one over R=k[x1,,xd]R=k[x_1,\ldots,x_d]. If EE is presented by a matrix φ\varphi with linear entries and the number of generators of EE is bounded locally up to codimension d1d-1, the Rees ring R(E)\mathcal{R}(E) is well understood. In this paper, we study R(E)\mathcal{R}(E) when this generation condition holds only up to codimension s1s-1, for some s<ds<d. Moreover, we provide a generating set for the ideal defining this algebra by employing a method of successive approximations of the Rees ring. Although we employ techniques regarding Rees rings of modules, our findings recover and extend known results for Rees algebras of perfect ideals with grade two in the case that rankE=1\mathrm{rank} \, E=1.

Keywords

Cite

@article{arxiv.2409.14238,
  title  = {On Rees algebras of ideals and modules with weak residual conditions},
  author = {Alessandra Costantini and Edward F. Price and Matthew Weaver},
  journal= {arXiv preprint arXiv:2409.14238},
  year   = {2024}
}

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22 pages