English

Morse index, Betti numbers and singular set of bounded area minimal hypersurfaces

Differential Geometry 2022-08-24 v3

Abstract

We introduce a combinatorial argument to study closed minimal hypersurfaces of bounded area and high Morse index. Let (Mn+1,g)(M^{n+1},g) be a closed Riemannian manifold and ΣM\Sigma\subset M be a closed embedded minimal hypersurface with area at most A>0A>0 and with a singular set of Hausdorff dimension at most n7n-7. We show the following bounds: there is CA>0C_A>0 depending only on nn, gg, and AA so that i=0nbi(Σ)CA(1+index(Σ)) if 3n+17,\sum_{i=0}^n b^i(\Sigma) \leq C_A \big(1+index(\Sigma)\big) \quad \text{ if $3\leq n+1\leq 7$}, Hn7(Sing(Σ))CA(1+index(Σ))7/n if n+18,\mathcal{H}^{n-7}\big(Sing(\Sigma)\big) \leq C_A \big(1+index(\Sigma)\big)^{7/n} \quad \text{ if $n+1\geq 8$}, where bib^i denote the Betti numbers over any field, Hn7\mathcal{H}^{n-7} is the (n7)(n-7)-dimensional Hausdorff measure and Sing(Σ)Sing(\Sigma) is the singular set of Σ\Sigma. In fact in dimension n+1=3n+1=3, CAC_A depends linearly on AA. We list some open problems at the end of the paper.

Keywords

Cite

@article{arxiv.1911.09166,
  title  = {Morse index, Betti numbers and singular set of bounded area minimal hypersurfaces},
  author = {Antoine Song},
  journal= {arXiv preprint arXiv:1911.09166},
  year   = {2022}
}

Comments

v2: Section 4 improved, minor corrections, results unchanged. v3: Corrections suggested by referees, correction suggested by Giada Franz and Santiago Cordero Misteli. To appear in Duke Math. J