Partial Betti splittings with applications to binomial edge ideals

TL;DR

This paper introduces partial Betti splittings, a generalization of Betti splittings, and applies this concept to binomial edge ideals, leading to new results on their Betti numbers and structure.

Contribution

It defines partial Betti splittings, extends their application to binomial edge ideals, and computes specific Betti numbers for these ideals, especially in trees.

Findings

Generalized Betti splitting to partial Betti splitting.

Described a partial Betti splitting for all binomial edge ideals.

Computed the total second Betti number for binomial edge ideals of trees.

Abstract

We introduce the notion of a partial Betti splitting of a homogeneous ideal, generalizing the notion of a Betti splitting first given by Francisco, H\`a, and Van Tuyl. Given a homogeneous ideal $I$ and two ideals $J$ and $K$ such that $I = J+K$, a partial Betti splitting of $I$ relates some of the graded Betti of $I$ with those of $J, K$, and $J\cap K$. As an application, we focus on the partial Betti splittings of binomial edge ideals. Using this new technique, we generalize results of Saeedi Madani and Kiani related to binomial edge ideals with cut edges, we describe a partial Betti splitting for all binomial edge ideals, and we compute the total second Betti number of binomial edge ideals of trees.