Simon's quantization conjecture for closed minimal surfaces in spheres

From papers

Let MM) be a closed surface minimally immersed in SN\mathbb{S}^N such that its image is not contained in any hyperplane of RN+1\mathbb{R}^{N+1}. Set S=h2S=|h|^2, where hh is the second fundamental form, and define

S(s)=2(s1)(s+2)s(s+1).S(s)=\frac{2(s-1)(s+2)}{s(s+1)}.

The Gauss equation gives 2K=2S2K=2-S, where KK is the Gaussian curvature. Simon's conjecture. If sNs\in\mathbb{N} and

S(s)SS(s+1),S(s)\leq S\leq S(s+1),

then either S=S(s)S=S(s) or S=S(s+1)S=S(s+1). Consequently, the immersion is one of Calabi's 22-spheres, with ambient dimension N=2sN=2s or N=2s+2N=2s+2, respectively. The first and second gaps are known, while the statement in this form concerns the broader quantization and gap problem for minimal surfaces in spheres.

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Sources & referencesView supporting material

Primary source

Weiran Ding, Jianquan Ge and Fagui Li, “Pinching rigidity of surfaces with parallel mean curvature vector in spheres”, arXiv:2607.23428 (2026).

Additional references

4 papers in this index state this conjecture (2024–2026). The statement above is taken from the most recent of them; the others are arXiv:2603.03070, arXiv:2601.07194, arXiv:2411.03917.

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