Pairs of Embedded Spheres with Pinched Prescribed Mean Curvature
Liam Mazurowski, Xin Zhou
TL;DR
This work proves that on the unit 3-sphere $S^3$, any admissible prescribed mean curvature function $h$ with the pinching bound $|h|<h_0$ (where $h_0$ is the real root of $\pi h_0^3 + 2h_0^2 + 4\pi h_0 - 8 = 0$, $h_0\approx 0.547$) admits at least two smoothly embedded $S^2$ with mean curvature $h$. The authors adapt the Simon–Smith min-max theory for the prescribed mean curvature functional $\mathcal{A}^h$ and exploit the Smale conjecture to identify the space of embedded spheres with $S^3$, then run a one-parameter and a four-parameter min-max to produce two distinct candidates and obtain a contradiction unless a second solution exists. An interpolation theorem combining Smale-type results with a filigree retraction controls deformations in the embedding space, allowing a Lusternik–Schnirelmann–type argument to complete the bifurcation into at least two solutions. The result advances topological existence theory for prescribed mean curvature surfaces and aligns with twin-bubble conjectures in three dimensions.
Abstract
Assume $h$ is a positive function on the unit three-sphere which satisfies the pinching condition $h < h_0 \approx 0.547$. We prove the existence of at least two embedded two-spheres with prescribed mean curvature $h$. The same result holds for sign-changing functions $h$ satisfying $\vert h\vert < h_0$ under a mild assumption on the zero set.
