Conjecture on Betti cones of hypersurface rings

Let QQ be a hypersurface ring of embedding dimension nn and multiplicity dd. Write (βi)i0(\beta_i)_{i\geq 0} for a formal rational Betti sequence, with standard basis vectors ϵi\epsilon_i in the ambient sequence space.

Betti-cone conjecture. The cone BQ(Q)\mathrm{B}_{\mathbb{Q}}(Q) is an (n+1)(n+1)-dimensional cone, and its closure is defined by the following (n+2)(n+2) extremal rays:

ϵ0,\epsilon_0, ϵi+ϵi+1(i=0,,n2),\epsilon_i+\epsilon_{i+1}\quad (i=0,\dots,n-2), d1dϵn2+i=n1ϵi,1dϵn2+i=n1ϵi.\frac{d-1}{d}\epsilon_{n-2}+\sum_{i=n-1}^\infty\epsilon_i, \qquad \frac{1}{d}\epsilon_{n-2}+\sum_{i=n-1}^\infty\epsilon_i.

This would give a description depending only on the embedding dimension and multiplicity of the hypersurface ring, extending the preceding description of the total hypersurface cone; the conjectural description for a fixed hypersurface ring remains to be established.

Sources & referencesView supporting material

Primary source

Christine Berkesch, Daniel Erman, Manoj Kummini and Steven V Sam, “Shapes of free resolutions over a local ring”, arXiv:1105.2244 (2011).

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.