English

Binomial ideals and congruences on $\mathbb{N}^n$

Commutative Algebra 2020-06-14 v1

Abstract

A \emph{congruence} on Nn\mathbb{N}^n is an equivalence relation on Nn\mathbb{N}^n that is compatible with the additive structure. If k\Bbbk is a field, and II is a \emph{binomial ideal} in k[X1,,Xn]\Bbbk[X_1,\dots,X_n] (that is, an ideal generated by polynomials with at most two terms), then II induces a congruence on Nn\mathbb{N}^n by declaring u\mathbf{u} and v\mathbf{v} to be equivalent if there is a linear combination with nonzero coefficients of Xu\mathbf{X}^{\mathbf{u}} and Xv\mathbf{X}^{\mathbf{v}} that belongs to II. While every congruence on Nn\mathbb{N}^n arises this way, this is not a one-to-one correspondence, as many binomial ideals may induce the same congruence. Nevertheless, the link between a binomial ideal and its corresponding congruence is strong, and one may think of congruences as the underlying combinatorial structures of binomial ideals. In the current literature, the theories of binomial ideals and congruences on Nn\mathbb{N}^n are developed separately. The aim of this survey paper is to provide a detailed parallel exposition, that provides algebraic intuition for the combinatorial analysis of congruences. For the elaboration of this survey paper, we followed mainly [Kahle and Miller, Algebra Number Theory 8(6):1297-1364, 2014] with an eye on [Eisenbud and Sturmfels. Duke Math J 84(1):1-45, 1996] and [Ojeda and Piedra S\'anchez, J. Symbolic Comput 30(4):383-400, 2000].

Keywords

Cite

@article{arxiv.2003.03861,
  title  = {Binomial ideals and congruences on $\mathbb{N}^n$},
  author = {Laura Felicia Matusevich and Ignacio Ojeda},
  journal= {arXiv preprint arXiv:2003.03861},
  year   = {2020}
}

Comments

Dedicated to Professor Antonio Campillo on the occasion of his 65th birthday

R2 v1 2026-06-23T14:08:07.336Z