The Eisenbud-Green-Harris conjecture for fast-growing degree sequences

TL;DR

This paper proves the Eisenbud-Green-Harris conjecture for certain degree sequences of regular sequences in polynomial rings, extending previous results and covering most known cases with fixed degrees.

Contribution

It establishes the conjecture for degree sequences satisfying specific inequalities, improving upon earlier partial results and including new cases.

Findings

Proves the conjecture for degree sequences with $d_i \\geq \\sum_{j=1}^{i-1}(d_j-1)$

Recovers all known fixed-degree cases except for a specific sporadic case

Includes several new cases beyond previous results

Abstract

Let $S$ be a standard graded polynomial ring over a field, and $I$ be a homogeneous ideal that contains a regular sequence of degrees $d_1,\ldots,d_n$. We prove the Eisenbud-Green-Harris conjecture when the forms of the regular sequence satisfy $d_i \geqslant \sum_{j=1}^{i-1}(d_j-1)$, improving a result obtained in 2008 by the first author and Maclagan. Except for the sporadic case of a regular sequence of five quadrics, recently proved by G\"unt\"urk\"un and Hochster, the results of this article recover all known cases of the conjecture where only the degrees of the regular sequence are fixed, and include several additional ones.