The index and finiteness conjecture for embedded minimal surfaces in the three-sphere

Let γN\gamma\in\mathbb{N}, and let ΣS3\Sigma\subset\mathbb{S}^3 be a closed embedded minimal surface of genus γ\gamma. Denote its Morse index by Ind(Σ)\operatorname{Ind}(\Sigma), and let ξγ,1\boldsymbol{\xi}_{\gamma,1} be the Lawson surface of genus γ\gamma. For kexcessNk_{\mathrm{excess}}\in\mathbb{N}, consider the closed embedded minimal surfaces in the round three-sphere with index at most 2γ+3+kexcess2\gamma+3+k_{\mathrm{excess}}. The index and finiteness conjecture. The index satisfies

Ind(Σ)2γ+3,\operatorname{Ind}(\Sigma)\geq 2\gamma+3,

with equality if and only if Σ\Sigma is congruent to the Lawson surface ξγ,1\boldsymbol{\xi}_{\gamma,1}. Moreover, for any given kexcessNk_{\mathrm{excess}}\in\mathbb{N}, the number of such surfaces is bounded above independently of γ\gamma. This would generalize Urbano's result to arbitrary genus; the proposed lower bound is substantially stronger than the best currently known lower bound, and the conjecture is motivated by index computations for minimal surface doublings.

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Primary source

Nikolaos Kapouleas and Jiahua Zou, “Index and nullity of minimal surface doublings, I”, arXiv:2512.07734 (2025).

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