Saturation Gap Conjecture for chopped ideals of general points

Let SS be the homogeneous coordinate ring of Pn\mathbb{P}^n, let ZZ be a general set of rr points, and let Id=I(Z)dSI_{\langle d\rangle}=\langle I(Z)_d\rangle_S. For positive integers n,d,rn,d,r satisfying r<hS(d)nr<h_S(d)-n, define γn(d,Z)\gamma_n(d,Z) as the least positive integer ee such that hS/Id(d+e)=rh_{S/I_{\langle d\rangle}}(d+e)=r. Saturation Gap Conjecture. The value γn(d,Z)\gamma_n(d,Z) depends only on n,d,rn,d,r, so that γn(d,Z)=γn(d,r)\gamma_n(d,Z)=\gamma_n(d,r), and

γn(d,r)=min{eZ>0hS(d+e)rk=1n3(1)k+1hS(d+ekd)(hS(d)rk)}.\gamma_n(d,r)=\min\left\{e\in\mathbb{Z}_{>0}\mid h_S(d+e)-r\leq\sum_{k=1}^{n-3}(-1)^{k+1}h_S(d+e-kd)\binom{h_S(d)-r}{k}\right\}.

This conjecture concerns the first degree in which the chopped ideal has the same Hilbert function as the ideal of the points. It is presented as implied by the Expected Syzygy Conjecture, while the paper proves the latter only in specified ranges and examples; no general resolution is given here.

Sources & referencesView supporting material

Primary source

Fulvio Gesmundo, Leonie Kayser and Simon Telen, “Hilbert Functions of Chopped Ideals”, arXiv:2307.02560 (2024).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.